Cecilia, Leo and Une are exploring the old outbuilding on the grounds of the guesthouse The Pearl. No one has opened the doors to the shed for decades, and there’s no telling what is in there. As it turns out, the outbuilding has been hiding some secrets, big and valuable ones, with ties back to when Albert Einstein himself was a guest at The Pearl. When he left the guesthouse, he left behind a riddle so complex that still no one has managed to solve it.

But maybe the Einstein mystery isn’t actually that difficult? Everything is relative, after all. Perhaps the reader will be able to solve the riddle before Cecilia, Leo and Une can?

The CLUE series’ name comes from the first letter in each protagonist’s name: Cecilia, Leo, Une, and Une’s dog Egon. In each of the series’ books a new mystery and a new ethical question is introduced along with the thoughts of one of the world’s most well-known philosophers. The CLUE books are best selling crime fiction for younger readers aged 9-12.