You'd think a ghost grandpa would be a great sidekick for a wannabe detective. Unfortunately, if there was a 'being a good ghost' exam, Jay's grandpa would fail spectacularly -- he hates walking through walls, he can't touch anything and he's rubbish at haunting.

Since his dad literally did a vanishing act (he's a magician), Jay Patel has turned detective, and now, with the help of his grandpa, he's on the case of a dead body that vanished from the library of his Glasgow primary school.

But what do diamonds, blackmail and dodgy launderettes have to do with it?

David Walliams meets Agatha Christie in the first book of a new laugh-out-loud, weird-and-wacky mystery series for younger readers by the author of Thorfinn the Nicest Viking.