'80s new wave band Volcanic Youth is in town to record a new album, but Kat feels troubled about the reunion after her contentious breakup with the band years ago. Mattie is assigned the unglamorous job of searching for a lost dog, but the case is put on hold when one of Volcanic Youth's members turns up murdered.

Mattie investigates a new victim: the band's manager, who was stabbed in the back with a kitchen knife. While searching for clues, Mattie finds the recording the lead singer made right before she died, but an incident from the past may be the key to solving the case.

The stage adaptation of Jane's book endures numerous snafus before opening night: electrical problems, feuding cast members, and a notorious arts critic writing a potentially bad review. Meanwhile, Mattie searches for new clues in the case of her missing mother, but an onstage murder brings her to the theatre.

Contending with another murder and a missing lead actress, the theatre company is forced to switch up the cast, but their production is a mess. Despite Mattie's objections, Beth and Cat continue to pursue leads on their own.