There has always been something unusual about Magnus Fin, a school misfit. On his eleventh birthday Magnus throws a message in a bottle out to sea, wishing for a best friend and to be more brave -- and he gets a lot more than he bargained for. Magnus discovers that he is half selkie -- part seal, part human -- and his selkie family urgently need his help.
Can Magnus save his new-found family from the evil force threatening all the ocean's creatures? And will he find the friend he has always dreamed of?