Events set in motion long ago come to their conclusion. Alison is honest with Noah -- and herself. A dispute between Cole and Scotty is followed by tragedy. Meanwhile, a turn in Noah's trial results in a shocking event.
The team has scattered, all living the ideal versions of their lives. Soon these “strangers” are drawn together to solve a supernatural mystery – the appearance of Ariel, the sprite bound to Prospero's service. Can the Librarians do what no other human has ever been able – turn their backs on their own ultimate happy endings?