Nick and Kate investigate when "mermen" begin stealing young women's minds; Kate's visiting sister is attracted to a guitar player named "Scar."

While they hunt a monster made up of human fat residue, Nick and Kate deal with Nick's former partner, Rich, who wants in on the case. To complicate matters, Rich is charged with a murder that the monster committed.

A "spider woman" preys on unsuspecting men in Chicago, wooing them into her web before slaying them. But a beautiful witness comes forth, helping Nick to clear the cobwebs from the clues.

An ancient Japanese mummy is awakened by a bolt of lightning, and sets out to re-create its tomb, including the three concubines buried with him. While working to capture it, Benson finds herself taken captive by the creature, which plans to sacrifice her---and two other women.

Nick finds an unusual way of taking a bite out of crime when he discovers that a pack of werewolves are terrorizing the city.

After witnessing a girl get abducted by a strange creature, Benson finds herself recruited into the elite Special Unit 2. She is paired with veteran O'Malley, and they attempt to recover the youngster.