An undercover operation takes a disastrous turn, leaving Lieutenant Vronsky suspended from duty under suspicion of murder. At last, the charismatic duo seizes the opportunity to repay him and work to clear his name.

In an upscale neighborhood of San Francisco, a killer is terrorizing the area, targeting women and leaving a red scarf as a signature of his crimes. A survivor of the attacks provides a crucial lead, guiding Carole and Sydney closer to uncovering the truth.