Despite the title, the Wishbone family are far from happy. In an attempt to reconnect as a family, Mum and Emma plan a fun night out. However, her plan backfires when an evil witch curses them, and they're all turned into Monsters.

Mia discovers her magic stone is part of an ancient prophecy and embarks on a thrilling journey to the farthest islands of Centopia to face a great evil, and shape her own destiny.