It has been nine months since Gordy and his friends, Max and Adilene, saved B.R.E.W. and the Vessel—the power source for the secret society of potion masters. Now, Gordy is starting the eighth grade, and has been trying new potion brewing techniques, but when he starts zoning out during practice, he knows something is wrong. Gordy and his friends continue to work on their potions, but when Gordy chooses Max as his lab partner, Adilene starts to wonder if she still has a place with her old friends. She turns to a new friend, Cadence, who might know a way to help Adilene become a potion master on her own. And in Greenland, Mezzarix has a chance to escape his Forbidden Zone—as long as he agrees to work with the mysterious Ms. Bimini and replicate an unusual solution known as "Silt." It could be just the weapon Mezzarix needs to destroy B.R.E.W. forever. With both B.R.E.W. and the Vessel in danger, and with the potion world in chaos, it's up to Gordy, Max, and Adilene to rally the remaining Potion Masters before it's too late.