A neighborhood is terrorized by group of young juvenile delinquents called The WolfPack. When a young father's infant child is seriously injured because of the WolfPack, he decides that the police aren't working fast enough to catch the ones who hurt his baby and sets out to infiltrate the gang himself and mete out the punishment they deserve.

A scientific team in Mexico discover a pool of unusual baby "octopus-like" specimens. Gathering a few for analysis back at the lab, it is soon discovered that the critters belong to a gangly six-foot half man/half octopus-like creature, that's pretty angry and wants her 'babies' returned…

It's nearly Christmas, but Mike Hammer is on the vengeance trail when Jack, his wartime buddy, is murdered. Hotheaded Hammer sets out to find the killer, working his way through an increasingly large pile of suspects (and corpses). Along the way, he meets a new love interest, psychologist Charlotte Manning, a treacherous Santa, a gangster named Kalecki, and two weird sisters, the Bellamy twins.