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.
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.
Sigmund accidentally breaks Aunt Zelda's bowl and decides to get money from his family's cave to replace it, but he is caught after curfew by the sea monster sheriff.