When small-town "puppy-saurus" Bubble Puppy gets picked to go against the reigning champ Boom Boom T-Rex in the Tough Roarier competition, it's a battle of strength, speed and, above all, heart.

Capt. Deemo and first mate Gil pilot their steampunk sub to different ocean habitats so they can deliver Friendship Day bubblegrams to all their friends; along the way, they find themselves being chased by a kraken.