After finding a classmate's corpse in her locker, perpetually unpopular Velma Dinkley is given an ultimatum: solve the mystery within 24 hours or face arrest for the crime. But as she reluctantly digs into the case, Velma is forced to confront the truth of her mother's own mysterious disappearance, and fend off the advances of her best friend, Norville.

Desperate to access her missing mom's case file, Velma strikes a deal with her former BFF Daphne - who may just have some secrets of her own. Then, while a sober Norville finds himself in with the wrong crowd, Fred claims innocence for a series of crimes.

In the wake of the murders, Principal Rogers enrolls all the female students in a self-defense class, forcing Daphne and Velma to work out their complicated relationship on the mat. Meanwhile, Norville attempts to pry the truth out of Fred the only way he knows how: cognitive behavioral therapy.

After yet another body turns up in town, Velma volunteers to rank Crystal Cove High's hottest girls to help determine the next victim. While trying to figure out what traits Velma finds attractive, Norville is pulled into a mystery tied to the history of the town - and Daphne's own dark past.

When Crystal Cove instates a nightly curfew, Velma is forced to spend the night with band geeks. But after taking advantage of Norville's good will (again), Velma finds herself stuck chasing clues with a newly woke Fred. At work on her own mystery, Daphne discovers a shocking connection to Crystal Cove's criminal underground.

After realizing the only way to stop her hallucinations is to resolve her daddy issues, Velma sets out to spend time with Aman - and convince him of the truth behind his wife's disappearance. Meanwhile, Norville takes the bad boy lifestyle for a spin, Daphne spends quality time with the Crystal Cove Gang, and Fred fights his father's anti-feminist ways.