Michael Fassbender) from his execution and hook him up to a machine which reads genetic memories from his code so he can relive his ancestor's experiences while jumping around tied to a giant metal arm with those experiences manifested around him as ghostly visages.
Still with me? In charge of the project is a die-hard believer (Jeremy Irons) and his daughter the scientist (Marion Cotillard) who needs a blood descendant of the last person to have the Apple to lead the Templars to it (on the assumption that no one could have possilby found and/or moved it in more than half a millennium). The only way to find the Apple is to have these decedents of various assassins relive the experiences (gaining knowledge, purpose, and murderous skills which, of course, will eventually backfire on the evil corporation).
So that's more or less the basis of the script which took three screenwriters (Michael Lesslie, Adam Cooper, and Bill Collage) to adapt from the popular video-game series. Added to that we have a collection of quality video-game cut-scenes expanded to the big screen, some pretty solid CGI, a series of action sequences of varying quality, and dramatic moments in which Fassbender and Cotillard doing their damnedest to try and make us care about anything we're watching on-screen.
Video games turned into movies don't fare well. Assassin's Creed is not the exception to this rule. Despite the talent on-screen and strong visuals, the movie flounders thanks to its gawdawful script. Holy crap, is this movie awful! Even if we accept the idea of "genetic memories," the movie still struggles to make a video game storyline work on film which in better hands might have been a diverting reversal of Twelve Monkeys but instead is a mishmash of half-assed ideas set to an overbearing score attempting to drown out just how awful everything is. Ridiculous while completely earnest in its depiction of events, Assassin's Creed is a dumpster fire of a film on the level of Max Payne, Underworld Evolution, or Blade: Trinity.