To break it down, in Valhalla Layla and the gang are looking for a temple that can save the world from ending.

It is hard to follow because the modern story has taken place over a series of games, dating back to AC1, and a lot of it is continued, and some storylines even end, in the books.

And no problem! I'm a huge AC fan so if there isn't anything you understand I'll be more than happy to answer!