After seeing a vision of her own death at the hands of a supernatural assassin, Baird tries to cheat fate and stop the deadly prophecy from coming true.

A Librarian from the past teams up with the Librarians of the present to take down an ancient and powerful enemy let loose in the modern day. When superfan Flynn is met with the prospect of teaming with his Librarian hero Darrington Dare, he could not be more excited, until Darrington leaves the Librarians with this dire warning: There can be only one Librarian - ignore at your own peril.

When a Civil War re-enactment in a town called Feud is plagued by ghosts, the Librarians have to uncover the truth of what really happened there over 100 years ago.

It's time to choose the singular Librarian to tether with Baird, but no one can decide so the Library takes it upon itself to help. Reducing the Librarians to their most primal selves and abandoning them in a landscape of their own nightmares, it's The Trial of the One - but can they regain their humanity in time to stop the bloodshed and prevent the death of two Librarians AND Jenkins?