A woman is found floating in a bathtub in a luxury apartment, but there is no initial evidence of how she died. The investigation reveals the victim was in the apartment of a man who took out a restraining order against her six months earlier. Across town, a music mogul is murdered in his penthouse. The victim's sister reports the killer is an intruder who has struck twice before. While collecting evidence, Stella accidentally cuts herself with bloodstained glass that may be infected with HIV.