Tommy loves nothing more than exploring the outdoors with his best friend, Tag the dog. Today he’s decided he’s going to the seaside, to search the rock pools and find some amazing creatures.When Tommy finds a little lost crab, he decides to take it home to live with his pet fish. But Tommy soon discovers that his aquarium might not be the best home for the crab.Luckily Mum is here to help! They take the crab back to his rock pool and reunite him with his family.Tommy learns an important lesson about baby animals in the wild.