Still separated by circumstance, Sigmund and the kids set out to find one another and continue their friendship. But between Sigmund's overprotective family and Captain Barnabus, who's still determined to prove sea monsters are real, will they ever manage to safely reunite?

When Robyn gives her mother Maxine a birthday present made by Sigmund, Maxine assumes that Robyn made it and is amazed by Robyn's artistic talent. Not wanting to disappoint her mother, Robyn goes along with the misunderstanding, which snowballs out of control. Meanwhile, Barnabus recruits a reluctant Johnny to help him plan a birthday surprise for Maxine.