When his memoirs are being turned into a movie, Timmy must deal with a buffoonish movie director, while his polar bear business partner Total wants to be reunited with his family and Timmy's father is back in town working at a bar.

There's a storm brewing over Eerie-on-Sea, and the fisherfolk say a monster is the cause. Someone has woken the ancient Gargantis, who sleeps in the watery caves beneath this spooky seaside town where legends have a habit of coming to life. It seems the Gargantis is looking for something: a treasure stolen from her underwater lair. And it just might be in the Lost-and-Foundery at the Grand Nautilus Hotel, in the care of one Herbert Lemon, Lost-and-Founder....