On the way to an exhibit at the museum, a mummy is revived by an electrical storm. However, this is no ordinary mummy, it was the most feared Japanese Samurai warrior that ever lived. The mummy wants all the things promised to him in the afterlife. To achieve this the mummy must collect everything he was entombed with, including three female concubines. He has the first two women and targets Kate as the third. For Nick, what started out as a standard Link investigation now becomes a rescue mission.

A Link is formed out of fat from liposuction patients from a plastic surgery clinic. The link kills the plastic surgeon when he gets in the way of the link's food supply and then disappears into the Chicago water system. The first detective on the scene is Rich Talridge, who was O'Malley's first partner before Nick was picked for SU2. Rich doesn't like that the case has been handed over to SU2 and tries to solve it himself which gets him in trouble. Kate and Nick and the rest of SU2 are left trying to track and get rid of the "Fat Link" before it kills again.

Some water Links, nicknamed Mermen, from two years ago have reappeared and are victimizing young women. The merman emits a high pitched sound which temporarily paralyzes the victim thus making it where the merman can empty the victim of their soul. This leaves the victim in a semi-vegetative state. The catch is that it only works on virgins. A tie-in to the story is that Kate's younger sister is visiting and dating a rather mysterious guy. Kate starts to suspect the guy may also be a merman and that her sister may be the next victim.