Prologue - Assassin's Creed Revelations
As the Prologue CS begins you meet Desmond -- or you meet him again if you have played the previous games -- and learn what has happened to him in the time since you last played him... And things have not gone especially well it seems -- as Desmond is in serious trouble, having fallen into a coma due to the bleeding effect of the Animus!
This is mostly a recap of what took place in the previous games, replaying the story arc -- and then you are told what has happened to you, about the fragmentation of your mind and the need for you to find the memory fragments inside the Animus, so that you can reassemble your brain mate.
The Prologue: Learning the Facts
Funnily enough you can hear them talking about you as they get ready to initiate another Animus linkup for you -- and then you find yourself laying on this oddly familiar beach with mood music playing in the background.
As you walk up the beach you run into a familiar face who tells you what has happened to you. Sort of... As the CS plays out you learn that this is the original test program for the Animus, and he tells you how serious your situation is. What will happen if you fail to locate a synch nexus...
When you get to the end of the beach he fills in the rest of the details, and points you towards the Hub. Just before you slide through into the Hub in the CS you learn that Lucy is dead. Then you get control over your body and what? You did not actually enter the Hub yet -- you have to do that again...