
A Librarian -- a custodian of a magical repository of the world's most powerful and dangerous supernatural artifacts -- from the past travels to the present and finds himself unable to return to his own time. When he returns to his castle, which is now a museum, he inadvertently releases magic across the continent. In order to set things right, he is given a new team of Librarians to help him clean up the mess he made.
Connor is forced to reconnect with people from his pre-Library life, and must defeat an old adversary who has grown powerful in his absence.
After a bachelorette party with Lysa's childhood best friend, the team wakes up in rough shape and hungover, with no idea how they ended up where they are.
While on a visit to a small-town festival, Connor encounters the very first vampire, and finds himself fighting the clock to save himself from turning into one.
When Vikram attempts to return to 1847, via a homemade time machine, he inadvertently travels the entire team back to the days of King Arthur, where they learn the truth about a Knight of the Round Table, Camelot, and Elaine.