Psychology professor and pop culture junkie Ashley McKennitt didn't plan to end up in the middle of a murder investigation. But when her best friend Cait's recently promoted homicide detective brother wants to pick her brain, Ashley jumps at the chance to gain real world insight into psychopathic behaviors. That's her first mistake. While Detective Jesse Malone is busy trying to validate his theory that a recent murder is connected to an unsolved cold case, Ashley notices that two recent murders have something in common: it appears the killer staged each scene, as though leaving clues for the detectives to solve a riddle, and those clues seem to illustrate the lyrics of popular songs. Could her encyclopedic knowledge of music really help Detective Malone catch a killer? Ashley's ego says yes, and she's hooked. Misstep number two.

By the time it's clear that a serial killer is prowling the streets of Sacramento, the clues left behind begin to hint at the next murder, and those murders start happening more frequently. While Detective Malone and his partner work frantically to find the killer and stop the rising body count, the killer starts a new game: stalking Ashley. Meanwhile, investigative journalist Cait is caught up in her own tangled mess involving a crooked Las Vegas casino owner suspected of money laundering, racketeering, and running a stolen car ring out of West Sacramento. The more it looks as though Cait's on-again, off-again boyfriend is somehow involved, the more determined Cait is to prove his innocence. As winter descends on the valley and the days grow shorter, Ashley and Cait find hope in short supply.