Someone is killing off potential Librarians and it's up to Flynn Carsen and his new Guardian, Colonel Eve Baird, to save the three that are left.

The Serpent Brotherhood is trying to return magic to our world. Flynn, Colonel Baird, and the potential Librarians must stop them before it's too late.

When the Serpent Brotherhood wants to kill Santa, the Librarians must rescue him and help him accomplish the true, secret purpose of Christmas.

When the dragons sleeping beneath the earth threaten to awaken and wreak havoc around the world, Flynn returns to help find their hidden treasure.

Baird begins moving through alternate timelines that reveal the destinies of the librarians.