Even though her teenage brother Matthew is a ton of trouble as far as Esmie's concerned, she feels sorry for him now he's been dumped by his girlfriend. What better way to cheer up Matty than to bake him a birthday cake - exactly the same cake, in fact, as their mum baked for his fourth birthday. Even better, Esmie and her friend Holly can concoct it secretly in their elderly neighbour's kitchen now she's away. But just as the friends embark on their secret scheme, a visitor arrives - who seems intent on robbing Esmie's neighbour. Can Esmie use all her detective skills to save the day?