While Velma goes to new lengths to solve the mystery of her mother’s disappearance – including teaming up with her former BFF turned nemesis, Daphne – Norville faces an enemy of his own… stoners.

When Principal Rogers enrolls all the female students in a self-defense class, Velma and Daphne must work out their complicated relationship on the mat. Meanwhile, Norville vows to get answers from Fred… by any means necessary.

Given 72 hours to uncover the identity of the serial killer, Velma is forced to live a lie with Norville, while Daphne and Fred concoct a story of their own to get back in with the Brains.

While Velma races against the clock to find the true serial killer, Daphne pursues a new career path, Fred finds a way to channel his rage, and Norville attempts to get as far away from his former best friend as possible.