When Cedric's new invention hits Lisa and becomes pregnant with a young creature with a confusing ancestry, Bert and his pals try their best to protect it from a new kind of threat-Violet Fox, the tabloids queen, and her trio of weasel goons!

Bert and Lisa are planning the wedding of their dreams. But Cyril Sneer has a different plan of his own: building a theme park atop Lover's Peak! Can Bert and his pals save the landmark before it's too late?