Johnny and Scott bring Sigmund home to live in their clubhouse, but the sea monster is nearly discovered by Zelda and the Sheriff when Sigmund's monstrous brothers come looking for him.
Johnny entertains at Zelda's bazaar by performing magic tricks (with sporadic assistance from Sheldon), while Scott displays his unicycling skills. Meanwhile, the Ooze family kidnaps Sigmund and tries to get him to join the Monster Militia.
Aunt Zelda goes to visit an ailing sister, leaving her humorless friend Gertrude in charge. Meanwhile, the boys are forced to contend with Sheldon's nephew, Shelby, who promptly turns Gertrude into a parrot.
Sheldon zaps Paul Revere into the clubhouse and then can't zap him home. Meanwhile, the Ooze family devises a scheme to swipe Sigmund's magic shell to help Blurp win back his girlfriend.
Sigmund falls in love with a canine named Fluffy. Meanwhile Zelda decides to clean the clubhouse and Slurp dresses up like a female movie star to try to lure Sigmund home.