User blog comment:The Crimson Eagle/Crimson Polls: 53/@comment-26894557-20141124052458/@comment-13471981-20141124074020

Modern day timeline: You are still working at Abstergo Entertainment when something goes wrong and the whole building is basically evacuated. You, alongside two private contractors, remain to repair the various software and relive Shay's memories.

References: Well, past characters appear evidently, but there's also a lot of documents that you can find, which refer to characters from other games, such as Unity, AC3, Liberation, Black Flag and so on. I think you kind of need a good background of the other AC games, cause it makes catching on to these references very fun, imo.