John is back from his killing spree saving a shipfull of African empaths from a burning ship. He has a relapse into Jack-the-riperism and kill one of the empaths. Dr Magnus kills him and later brings him back to life, imprison him in a cell.
One of the empaths have an episode warning everyone for something evil in the house. Shortly afterwards the house goes into security lock down.
Kate and big guy is trapped in the elevator. Magnus and John are trapped in his cell. Henry is locked in in the infirmary with one of the empaths. Something is trapped in the house and it is trying to kill them.
One of the best episodes ever!