The clever Bacon brothers are a bit younger than Jerry and Maya, and they are The JerryMaya Detective Agency’s biggest fans! The Bacon brothers solve slightly nicer crimes, but in The Secret Key they are given a tricky challenge. The brothers find a mysterious key and no one knows where it leads. It can lead almost anywhere!

Everyone in Valleby seem to have issues with their keys. Muhammed Karat has been locked out of his store, Frida at the animal store cannot get to the animal food, and Fransy Vik has lost the key to her locker by the swimming pool. The Bacon brothers have to use their best detective knowledge to be able to help the town.