Deus Vult and Salve fellow assassin,
Welcome to the 3rd Crusade and the renissance where you will learn what happened to the ancestors that had to fight long and hard to reach their respected precursor artefacts Altaïr Ibn-La'Ahad and Ezio Auditore Da Firenze.

Assassins Creed 1(The First Original Game)

In 2012, bartender Desmond Miles is kidnapped by agents of Abstergo Industries, the world's largest pharmaceutical conglomerate. Under the guidance of Dr. Warren Vidic and his assistant Lucy Stillman, Desmond is forced to participate in a series of trials revolving around the "Animus", a machine capable of translating the genetic memories of his ancestors into a simulated reality. Vidic instructs him to relive the early years of Altaïr Ibn-La'Ahad, a senior member of the Assassin Brotherhood during the time of the Third Crusade. His investigation reveals that Altaïr, blinded by arrogance, botched an attempt by the Assassins to retrieve an artifact, the Piece of Eden, from the forces of Robert de Sablé, Grand Master of the Knights Templar, leading to the death of one Assassin, and severely wounding another in the process. Though Altaïr manages to partially redeem himself by fighting off a Crusader attack on the Assassin home base of Masyaf, his mentor and superior, Al Mualim, orders him to assassinate nine individuals in order to regain his honour:

Tamir, an arms merchant selling weapons to both sides.
Garnier de Nablus, a prominent Crusader conducting alchemical experiments on the sick.
Talal, the leader of a gang of slavers.
Abu'l Nuquod, a pompous trader stealing money meant to fund the war.
William V, Marquess of Montferrat, the cruel and abusive regent of Acre.
Majd Addin (based off Baha ad-Din ibn Shaddad), a tyrant who rules Jerusalem through fear.
Master Sibrand, a paranoid knight planning to betray the Crusaders.
Jubair al Hakim, a scholar using his position to seize and destroy all written knowledge.
Robert de Sablé, the grandmaster of the Templars, the ancient enemies of the Brotherhood.

As Altaïr eliminates each target, he learns that all nine are secretly members of the Templar Order and that they were conspiring to locate an "Apple of Eden", a relic of a long-forgotten civilization said to possess god-like powers. During an initial attempt to assassinate Robert at a funeral in Jerusalem, Altaïr discovers that Maria, a young Templar agent, had disguised herself as him in order to buy enough time for Robert to negotiate an alliance between the Crusaders and Saracens against the Assassins. Sparing her life, Altaïr catches up to Robert in the camp of King Richard I and exposes his crimes. Unsure of whom to believe, Richard suggests a one-on-one duel to decide the truth, remarking that God will decide the victor. Upon sustaining a mortal wound from Altaïr, Robert confesses that he did not act alone, Al Mualim had also sought the Apple and betrayed the Templars in the process. Returning to Masyaf, Altaïr finds both the inhabitants and Assassins under the control of the artifact, which is now held by Al Mualim. With the help of several Assassins brought in for backup, Altaïr storms the citadel and confronts his mentor in the gardens. Using the Apple, Al Mualim battles his apprentice with illusions before resorting to single combat. Altair stabs him with his hidden blade and tries to destroy the Apple, but instead unlocks a secret map within that reveals the location of countless other Pieces of Eden around the world.

With the trials complete, Vidic reveals that Abstergo is but the modern incarnation of the Templars. Lucy, who turns out to be a mole planted by the modern-day Assassins, mysteriously disappears. While awaiting her return, Desmond discovers strange drawings covering the walls of his room, which foretell a catastrophic event that will wipe out humanity.

Assassins Creed II

After the events of Assassin's Creed, test subject Desmond Miles is rescued from confinement by undercover Assassin Lucy Stillman and taken to a remote safe house, where he meets her team, consisting of historian and analyst Shaun Hastings and technician Rebecca Crane. Using design plans stolen by Lucy, they have constructed their own version of the Animus, dubbed "Baby", which they intend to use to train Desmond as an Assassin through the so-called "Bleeding Effect", which allows the user to learn all their ancestor's skills instantly. Desmond is assigned to investigate the memories of his ancestor Ezio Auditore da Firenze, starting with his birth to a wealthy Florentine family in the late 15th century.

Assassin's Creed II's plot includes the fictional depictions of historical characters including Niccolò Machiavelli and Rodrigo Borgia, later known as Pope Alexander VI. The story then skips forward several years, with Ezio growing into a charismatic but reckless young man in the time of the Renaissance. After his father and brothers are hanged after being framed for treason by a corrupt magistrate, Ezio kills him and flees to his ancestral home of Monteriggioni with his mother and sister. There, his uncle Mario explains that both he and his late father served an ancient order known as the Assassins, and agrees to train Ezio in stealth and combat. With his new abilities, Ezio embarks on a quest to kill the men responsible for arranging his father's death, including politicians, bankers, mercenaries, and merchants aligned to the Pazzi and Barbarigo families. The search takes him to cities such as Florence, San Gimignano, Forlì, and Venice. During his journey, Ezio also makes a number of new allies, including philosopher Niccolò Machiavelli and inventor Leonardo da Vinci, the latter of whom provides him with new equipment based on information left by Altair's Codex. While in Venice, he learns the identity of the Templar grandmaster known as "the Spaniard": Rodrigo Borgia, who has been planning to secure all of Italy for the Order by unifying the most influential families behind his leadership. Dressed as a soldier, he confronts Rodrigo while helping him transport an Apple of Eden to Rome. Armed with the papal staff—which turns out to be a Piece of Eden—Rodrigo reveals his intention to unlock the "Vault", a chamber he believes to contain a power greater than any the world has ever known. He manages to escape, leaving the Apple in Ezio's possession. As a reward for service, Mario has him formally inducted into the Assassins.

Around this time, Desmond uncovers a random memory left over from his time at Abstergo, in which Altair is shown impregnating Maria Thorpe, a Templar he encountered in the previous game. He also finds a series of glyphs similar to the drawings he found in his cell, which, when deciphered, reveal a vision of two human slaves stealing an Apple. The video ends with the ASCII codes (in binary) for "EDEN" (01000101 01000100 01000101 01001110). The team theorizes that the two humans may be Adam and Eve, the first man and woman.

With several sections of memory too corrupted to access (later made available as DLC Sequences), the team sends Desmond to the final memory, set in 1499. With Rodrigo now secure in his position as Pope Alexander VI, Ezio infiltrates Vatican City during Mass and beats him in a fistfight. Rather than kill his nemesis, he lets him live with the knowledge that he has failed.[7] Combining the Apple and Staff, he opens the entrance to the vault. Inside, he is contacted by a strange woman named Minerva. Aware that Desmond is listening, she explains how her people, the "First Civilization", created humanity to serve them, but were subsequently destroyed by an unknown catastrophe. The survivors joined forces with their former servants, building a network of vaults to both preserve their technology and culture and serve as a preventative measure against a future disaster. Before vanishing, she tells Desmond that only he has the power to fulfill this "prophecy", leaving both him and Ezio confused as to what she means.

Shortly thereafter, Abstergo agents led by Vidic enter the hideout, forcing the team to abandon everything except the Animus. As they head to a new location, Lucy informs Desmond that the Assassins have detected strange occurrences in the Earth's magnetic field; a solar flare scheduled to pass the planet in a few months would likely trigger the same event that ended the First Civilization. Desmond prepares to reenter the Animus, beginning the story of Assassin's Creed: Brotherhood.

Assassins Creed BrotherHood

Desmond's story continues where it left off, in 2012. After escaping the Templars' attack at the end of Assassin's Creed II, Desmond Miles, Lucy Stillman, Rebecca Crane, and Shaun Hastings flee to Monteriggioni, establishing a new hideout in the ruins of the Villa Auditore. After restoring the electricity in the old tunnels under the villa, the player once again takes control of Ezio Auditore through Desmond's genetic memory, using the Animus 2.0 (which is the game's memory interface). Their mission is to find the Apple of Eden, an important and mysterious artifact that could prevent the impending disaster that is coming in that same year, believed to be perpetrated by the Templars.

Ezio's story continues in 1499, where he exits the Vault, confused by what he saw inside. He escapes Rome with his uncle, Mario Auditore, and returns to Monteriggioni. Once home, Ezio is comforted by the prospect that his personal vendetta is over; however, Niccolò Machiavelli challenges Ezio's decision to leave Rodrigo Borgia (now Pope Alexander VI) alive. The following morning - New Year's Day - Monteriggioni is besieged by Cesare Borgia, son of Rodrigo. Mario is killed at the hands of Cesare himself, and the Apple lost to Cesare and the Templars. Ezio escapes with his family and travels once more to Rome, the center of Templar power in Italy, once again seeking vengeance against the Borgias. There, he discovers that the Assassins are failing in their fight against corruption. Determined to rebuild the Guild, Ezio convinces Machiavelli that he has what it takes to lead while assembling a Brotherhood powerful enough to destroy the Templars and his new nemesis, Cesare.

Over the next four years, Ezio executes various tasks meant to cripple the Borgias' hold in the capital, sabotaging Cesare's resources and assassinating key people close to and/or working with him in the process, and slowly restoring Rome to its former glory. After returning the Roman Assassins to full strength, Ezio is given the rank of Il Mentore (Italian for "The Mentor"), and made de facto leader of the Assassins in Italy. During this time, Ezio's sister Claudia is also made an Assassin.

Cesare, learning of Ezio's actions, confronts his suspicious father and desperately asks for more money, and the Apple itself. Rodrigo refuses, cautious of provoking the Assassins, and attempts to poison his son, realizing that Cesare's lust for power cannot be held at bay. Cesare, however, turns the tables on his father and kills him instead. Ezio witnesses this and, after learning of the Apple's location, retrieves it from within St. Peter's Basilica. Ezio uses it to overwhelm Cesare's forces and gradually withdraw the backing of his supporters; Cesare is finally arrested by Pope Julius II's Papal Army after Ezio and the Assassins confront him and kill his remaining followers.

Sometime later, Ezio uses the Apple once more to check on Cesare, who has broken out of prison and, after gaining the support of his new patron, John III of Navarre, laid siege to the city of Viana, in Navarre.[19] Ezio encounters Cesare on the battlements of a crumbling castle and fights him.[20] Cesare claims that he cannot be killed by the hand of a mortal man, thus inciting Ezio to "leave [him] in the hands of fate" by dropping him off the battlements to his death. Ezio then takes the Apple and hides it in a First Civilization Temple built underneath the Roman Colosseum.

Using the coordinates taken from Ezio's memories, Desmond, Lucy, Shaun and Rebecca travel to the Temple, intending to use the Apple to locate the remaining Temples and keep the other Pieces of Eden out of the Templars' hands. As Desmond makes his way into the Temple, he is confronted with holographic apparitions of a being called Juno, who appears to be of the same race as Minerva; however, she is neither audible nor visible to Lucy, Shaun, or Rebecca. Most of her comments center on humanity's lack of knowledge. She states that humanity is "innocent and ignorant;" that people were not built to be wise, having been given only five of the six senses: sight, smell, taste, touch, and hearing, but lacking knowledge. Her careful cadence then drops, as she suddenly becomes angry, yelling, "We should have left you as you were!"

As Desmond approaches the Apple and touches it, time freezes around him, though he can still move and speak. Juno cryptically states that Desmond is descended from her race, and is their enemy; she also says there is a woman who would accompany him through "the gate," but must not be allowed to. She takes control of Desmond's body and forces him to stab Lucy in the abdomen. Both fall to the ground, with Lucy dead and Desmond entering a coma. As the credits roll, two men are heard discussing whether to put Desmond back in the Animus.

Assassins Creed Revalations

Following the ending of Brotherhood, present-day protagonist Desmond Miles has fallen into a coma due to the combined stress of being forced to kill Lucy Stillman and being controlled by Juno, the hologram attached to the Apple of Eden. While Shaun Hastings stays behind in Rome to attend Lucy's funeral, Rebecca Crane takes Desmond to New York City and meets with his father, William Miles. In an effort to save Desmond's mind, the duo places him back in the Animus, though this time in the machine's safe mode, known as the "Black Room".

Upon awakening on Animus Island, the original Animus testing program located within the Black Room, Desmond meets the preserved consciousness of Clay Kaczmarek (Subject 16), who occupied Abstergo's Animus before him. Clay explains that Desmond's mind is broken, and the only way for him to repair it is by reliving his ancestors' memories until there is nothing left for them to show Desmond, at which point the Animus can separate Desmond from Ezio and Altaïr, and awaken Desmond from his coma.

Desmond enters the Animus Island's memory portal, which places him back in the perspective of Ezio Auditore. Four years after ending the life of Cesare Borgia, Ezio has traveled to the former Assassins' fortress in Masyaf to discover secrets Altaïr had previously discovered, and find the true purpose of the Assassins. Upon arriving, he finds Masyaf taken by the Templars, who mark him for death. Ezio escapes to the bowels of the castle, where he discovers the entrance to Altaïr's library. He learns that five disc-like "keys" are required to unlock the door. He also learns that the Templars have discovered one underneath the Ottoman Sultan's palace. The rest lie hidden in Constantinople, capital city of the Ottoman Empire. He travels there and is greeted by Yusuf Tazim, leader of the Turkish Assassin Order, and befriends a young student named Suleiman. Ezio learns that the keys were hidden in the city by Niccolò Polo. While searching for the old Polo trading post, Ezio encounters and befriends Sofia Sartor, a young Italian traveller and book collector, and eventually falls in love with her. Ezio discovers the locations of the remaining keys with Sofia's help, all the while keeping his intentions, growing feelings and position a secret from her.

Meanwhile, Constantinople is in chaos due to conflicts between Prince Ahmet and his brother Selim, who are quarreling over who will inherit the Sultanate. Caught in the middle of the conflict, Suleiman reveals to Ezio that he is an Ottoman prince (Selim's son), and that he suspects the Templars are behind the feud. Ezio uncovers evidence that Manuel Palaiologos, with Templar support, is attempting to raise an army to overthrow the Ottomans and re-establish the Byzantine Empire. Ezio kills Manuel and recovers the final key, only to discover that Ahmet is the true mastermind of the Templar plot to open Altaïr's library.

During these events, Ezio uses the keys in his possession to witness Altaïr's life after the events depicted in the first game. After killing Al-Mualim, Altaïr took possession of the Apple of Eden and assumed leadership of the Assassins. One of the Assassins, Abbas, did not support Altaïr due to past events, and for killing Al Mualim. When Altaïr and his wife Maria left Masyaf for 10 years to repel the Mongol invasion, Abbas staged a coup d'etat, seizing control of the Assassins and executing Altaïr's youngest son Sef. Altaïr sought revenge; but as Maria tried to stop him, another Assassin stabbed Maria in the back. Altaïr was forced to flee with his elder son, Darim, and went into self-imposed exile for 20 years. Altaïr eventually returned to Masyaf, killed Abbas, and took his rightful place as the leader of the Assassins. In the process, Altaïr told the dying Abbas the truth of the latter's father's death. Years later, Altaïr encodes his memories on the five keys Ezio would find, entrusting them to Niccolò.

Returning to Constantinople, Ezio discovers that Ahmet has killed Yusuf and kidnapped Sofia, demanding the keys in exchange for her life. Ezio agrees, but immediately gives chase upon ensuring Sofia's safety. He recovers the keys, but before he can deal with Ahmet, Selim arrives with his armies and executes Ahmet himself, stating that their father "made his choice". Due to his son Suleiman's endorsement, Selim spares Ezio, but tells him to leave Constantinople and never return. After completing this memory, the Animus begins to delete excess data—including Animus Island. Clay imprints his genetic memories onto Desmond before sacrificing himself to prevent Desmond from being deleted by the Animus.

Ezio and Sofia return to Masyaf, where Ezio uses the keys to unlock Altaïr's library. He finds it empty except for Altaïr's skeleton and a sixth key. He discovers that the library was not meant to hold books—rather, it was a vault meant to house Altaïr's Apple of Eden. Through the key, Ezio learns that Altaïr had sealed himself inside to preserve its secret from the Templars. Ezio leaves this Apple in the library, stating that he had seen enough for one life. He then begins talking directly to Desmond, not knowing exactly who (or where) he is, but knowing that he is watching. While talking he discards his weapons, signifying his retirement as an Assassin. He tells Desmond that he realises that he is a conduit for a message, and expresses hope that Desmond will be able to find answers to the questions he and Altaïr had worked so hard to uncover.

Suddenly, Desmond is approached by Jupiter, a member of the First Civilization. He explains that the First Civilization had built numerous vaults to study methods to save the planet from destruction. All of the data collected was transmitted to a central vault, where the data was tested. None of the methods were effective, however, and they failed to stop the solar flare from destroying their civilization. Jupiter shows Desmond the location of the central vault, which from the map is located somewhere in New York, and tells him that he must save the planet from an impending second solar flare.

Upon hearing Jupiter's words, Desmond awakens from his coma and finds Rebecca and William standing with him, along with Shaun, who has returned from Rome. Desmond states that he knows what they must now do; meanwhile, the central vault activates underground.