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.

To free Baba Yaga and Renfield from the clutches of Monster Hunter Mila Starr, the Wishbone Family once more transforms into a Vampire, Frankenstein's Monster, a Mummy and a Werewolf. Aided and abetted by their three pet bats, our Monster Family zooms around the world again to save their friends, make new monstrous acquaintances and finally come to the realization that 'Nobody's Perfect' - even those with flaws can find happiness.