Simon Thorn and the Shark's Cave

Simon Thorn has only recently discovered that he's an Animalgam, a member of a secret race of people who can shift into animals, and found a home where he truly belongs. But not everything is as good as it seems. Simon's evil grandfather, Orion, is bent on taking over the entire animal kingdom, and to do so, he'll need to gather the pieces of a terrible weapon, one that could shred the very foundations of the Animalgams' world ... unless Simon can gather the pieces first.