The Moochmore girls are certain they all suffer from some kind of undiagnosed mental illness - because if they’re not crazy then they’re just unpopular. Their mother Shirley - unable to cope with her demanding daughters and unsupported by her philandering politician husband, Barry - suffers a nervous breakdown. After Barry commits his wife to a mental hospital (telling his constituents that "she’s on holiday") he finds himself alone with 5 teenage girls he barely knows. Desperate, he impulsively picks up a hitchhiker named Shaz and installs her in his home as nanny to his daughters.

Shaz is charismatic, hot-tempered, inspiring and completely crazy. She transforms the girls - especially the oldest, 16 year old Coral. The Moochmore girls go from being the town’s biggest jokes to becoming forces to be reckoned with. Shaz even springs Shirley from the mental hospital and forces Barry to face up to his family responsibilities.

But Shaz has a secret. And it involves Coral’s boss, shark hunter, Trevor Blundell. As Coral discovers the real reason for Shaz’s visit to the town of Dolphin Heads, she must make a terrible decision: fulfill her moral obligation and follow Shaz into complete madness... or betray the woman who changed her life.