Fifteen-year-old Miss Penelope Lumley, a governess trained at the Swanburne Academy for Poor Bright Females, takes the three Incorrigible Children of Ashton Place to London, England, and learns they are under a curse.

When Clara vanishes after the puppeteer Grisini and two orphaned assistants were at her twelfth birthday party, suspicion of kidnapping chases the trio away from London and soon the two orphans are caught in a trap set by Grisini's ancient rival, a witch with a deadly inheritance to shed before it is too late.

When a glowing lost and found box appears and stranger-than-normal things begin to happen at Strangeville School, it is up to Harvey and his friends to solve the mystery of a fifty-year-old curse before it is too late.

When she incurs Neptune's wrath by finding a diamond ring buried under rocks in the ocean, Emily is put under a curse that will force her to choose to be either a mermaid or a human and split up her parents forever.