The first DLC for “Assassin’s Creed 3”, titled “The Tyranny of King Washington”, is officially part of the “Assassin’s Creed” mythology. Most gamers assumed that the DLC would not count in the canon of the games, as it’s obviously from an alternate reality where George Washington became king instead of president. Today, the games director Marc-Alexis Côté put an end to that thought.
By the end of the last episode you will see how this relates to Connor and the real George Washington. This experience is canon.
As for the story, Connor wakes up one day to find the world has turned upside down and gone completely insane. George Washington went on a massive power trip and declared himself king, his mother is suddenly alive, and his tribe can now use superpowers after drinking a hallucinogenic tea. Connor himself can do some amazing things, like turn invisible or do a flying attack.
Right from the start, Connor is questioning that things aren't right. He's asking 'Why is my mother alive?' You understand that this is all related to Connor but you don't know how or why it is canon. But, by the end, you will understand - and it's a great, clear-cut end to the story.