Meet McGrowl. He's the new superhero in town - a sweet and shaggy pooch who happens to have some amazing bionic powers.
When a heroic deed lands McGrowl in the local newspaper, Edwina Tuttle spots her former pet - and invites McGrowl to her house for a visit. So Thomas and McGrowl set off on an exciting journey to see Edwina. But their trip becomes a wild-goose chase. The mastermind behind it all may be the evil Milton Smudge. And this time, he's determined to trap McGrowl - no matter what it takes!