In a startling turn of events, Alice-Miranda unexpectedly finishes the school term earlier than planned. Holidays should be a time for fun and a chance to catch up with friends, but it seems all is not well at Highton Hall. There is trouble afoot with the family business and it's got everyone worried. Scores of people have been struck down with a mystery illness and it looks as if Kennington's may be responsible.

Meanwhile, there is an annual garden party to prepare for. And the whole village is invited! Throw in an intriguing neighbour, a runaway and a swindler and it may be the perfect recipe for disaster. Alice-Miranda will have to trust her intuition to find the key to unlock this mystery.