Mark and Randall go down to Hell to spend Halloween with Callie's family, who have some special plans for Mark.
Mark tries to help Leonard with his wand issues, disastrously; Twayne meets his soulmate.
Mark has to deal with a clingy new roommate after Randall leaves to join a zombie cult.
A Kong is put on leave from his job after suffering an OCD attack, leaving it up to Mark to help find him work. Unfortunately, budget cuts have forced Twayne to shut down Mark's department for the rest of the year, just in time for him and Callie to attend the lavish Demon Convention in Atlantic City. As Callie battles her sudden unexplained attraction to Twayne, Mark and a recently bisected Randall make their way to Atlantic City to get Social Services reinstated, so that Kong (and Leonard) can get back to work.
Grimes' goon squad prevents a handsome young vampire from biting his human girlfriend, and the two are put under Mark's care until they can undergo a proper vampire conversion. Unfortunately, the young woman turns out to be Grimes' daughter, and he will stop at nothing to prevent her from becoming a hated bloodsucker. Mark is reluctantly caught in the middle of this family crisis, and although he initially rejects Grimes unabashed prejudice, a strange citywide epidemic causes him to have some doubts...