When the tunnel world is having an annual event, Paracelcus makes plans to crash the event and do something. When all of the participants arrive, including some friends from the surface, things seem to be OK until Narcisa shows up. It seems she had encountered Paracelcus earlier who had in his possession someone's head who then tried to kill her. They assume Paracelcus is there in disguise. Catherine and Vincent deduce it must be someone from the surface but there are only three whom he knew before he was banished so they try to figure out who could it be.
A young man gets lost in the tunnel world and he is found by the inhabitants. They're uncertain if they should let him go because they're not sure if he can be trusted to keep their secret. But when a search party comes looking for him, they decide to try to convince him to keep their world a secret.
Kanin, a resident of the Underworld, goes into a store on the surface and is recognized by a woman as the man who killed her son, years ago. She then goes to the police and D.A. demanding that they bring him in. Catherine speaks to them and Kanin doesn't want to leave his family. But Vincent tells him that he should take responsibility for his actions.