Marvin must track down a missing teenage girl after her romantic interest is discovered decapitated.

Marvin's investigation into an unknown serial killer, coined "the Boner" by local media for mutilating their victims with animal bones, is interrupted by a production crew who's in town to turn the case into a true crime limited series. Meanwhile, Stan grows close with the actor playing Marvin.

After being forced to take a desk role in the office, Flute decides to lead a double-life and become a dog-themed superhero named McSnuff.

Flute enters the Grimsburg Miniature Competition and is accused of murdering the judge, Jebediah Cupps, after he disqualifies him. Flute tries to clear his name at the local middle school by recreating a miniature model of the crime scene. Then Stan joins his school's Trauma Club.

In an attempt to stop Marvin from forgetting about him, Stan and Dr. Pentos create a diabolical plan staging his disappearance.

Marvin and the team investigate the death of a morning TV host, in which former child star Lil' Betsy is the main suspect. In the process of the investigation, Marvin becomes consumed with his newfound celebrity status. With everyone rallying around Lil' Betsy, Marvin is determined to find her guilty.

During the town's talent show, a serial killer targets the winner as Marvin finds himself at the judging table to capture them in the act.