[1][2] The film starts off with a scene from the novel Moby Dick, with a whaler on a stormy sea in the 19th century, chasing "the white whale".
While they play together, Nelson hears the wail of a beached whale named Tonga from the local coast, and jumps out of his pool, over the cliff beside, and dives into the ocean on the other side, to check what is going on, with Dot coming along.
Dot walks up on land to talk with Tonga, but becomes upset as two boys, Alex and Owen, stand and throw sand on the whale.
After a long adventure, Dot and Nelson reach Antarctica and meet the aged and wrinkly whale, but Moby Dick will not ask Tonga to return to the sea.
Dot returns from the sea and makes up a new plan with Alex and Owen in order to save Tonga, and let her share the pool with Nelson.
As they finally find a company which can help them (in return for a big sum of money), they face the problem of lacking payment.