Anna and Holly Burnbright, together with their friend Prince Pepino, are trying to earn enough money to go on the intergalactic holiday of a lifetime. What they need is a holiday job. So when a tall, elegantly dressed lady called Mademoiselle Malypense tells them she needs help to organise the Francian Royal Wedding, they jump at the chance. She's promised to pay handsomely!

The children are whisked away to begin the preparations, but it's not long before Holly smells a rat. Why does Mademoiselle Malypense insist they complete their tasks in secret? And isn't there something odd about a garlic-flavoured wedding cake? Could there be more to this royal couple's wedding day than meets the eye?