As Angel tries to deal with the loss of his son while cleaning up the earthquake damage upstairs, a potential Angel Investigations client is infected by a transparent slug-like parasite in the hotel lobby. He goes to the juice bar across the street, where he chugs glass after glass of juice, saying, "We are thirsty." When Lorne informs him of the disturbance at the juice bar, Angel brings the infected man back to the hotel, where he collapses into a pile of human dust. When a slug-creature exits from the dust, the gang realizes the man was actually a parasitic host. The hotel is locked up tight and Angel sends everyone out with weapons to hunt for the slug. As they search, they realize that the hotel is teeming with the parasites, which suck their human hosts dry. Angel suspects that the infestation is a result of "thaumogenesis", a price for the dark magics that Angel conjured to try to find his son.