Plot
In New York City, an old mouse named Connors tells his grandchildren the supposedly "true" story of the RMS Titanic, after discouraging one of his grandchildren from playing with a shark whistle, telling him it will attract Mr. Ice.
In April 1912, Connors was a young sailor mouse on the Titanic's maiden voyage from Southampton to New York. He also befriends a young Brazilian mouse named Ronny, who enjoys playing soccer, and falls in love with his sister Stella. Meanwhile, a rich aristocratic woman named Elizabeth, her family, and a young Romani-Spanish man named Don Juan board the Titanic, which immediately sets off.
Connors and Ronny learn that Elizabeth's family is insisting that she be married to a whaling mogul named Everard Maltravers, despite her adamantly refusing. When Elizabeth goes to the bow of the ship that night, some dolphins begin communicating with her, explaining its possibility through magic moonbeams catching her tears as they fell into the water. They inform her that Maltravers only wishes to marry her to get permission from her father to have global access to the oceans for his whaling operations.
Connors and Ronny introduce themselves to Elizabeth and offer to help her. Listening to their advice, Elizabeth tells her father she doesn't want to marry Maltravers, to which he accepts, despite having insisted she marry Maltravers earlier. Meanwhile, Don Juan's Rough Collie dog Smiley meets Connors and Ronny, who help to arrange a meeting and dance for Elizabeth and Juan, who fall in love.
Having failed to achieve their wedding plan, Elizabeth's stepmother and Maltravers decide to resort to drastic measures. They decide to hold Elizabeth's father up at gunpoint, force him to sign the whaling concession, and tie him up. At the same time, Mr. Ice, a tiger shark who escaped from prison is asked to arrange the destruction of the ship. Mr. Ice and his gang of sharks prepares to sink the Titanic. Maltravers' manservant Geoffreys asks the radio man to send an urgent wire from Maltravers to his whaling ships by telegraph, but the mice chew apart the wires to stop it from being sent.
Ice and his gang fool a giant innocent-minded octopus named Tentacles into heaving an iceberg to the surface of the ocean. The Titanic crashes into the iceberg, during which Maltravers and his entourage flee the ship in a lifeboat. In order to fix the telegraph wires, the mice enlist the help of a French mouse named Camembert, who insist they tie the wires to his moustache, seemingly electrocuting him to death.
Elizabeth and Juan manage to save her father and escort him to a lifeboat. Suddenly, several whales and dolphins arrive to help with the rescue, while a guilt-ridden but determined Tentacles tries to hold the bow and the stern together as they are splitting apart, and keep the ship on the surface for as long as possible. Everyone jumps off the Titanic into the sea and are saved by a whale. Once everyone on the ship has been saved, the Titanic finally sinks, taking Tentacles with it and seemingly crushing him. In the morning, the passengers are taken aboard the RMS Carpathia. The said ship arrives in New York and disembarks the passengers. Elizabeth and Juan are married, as are Connors and Stella. Everyone celebrates at the Brooklyn Bridge, where Tentacles and Camembert show up, inexplicably unharmed.
Back in modern-day New York old Connors tells his grandchildren that whales are still hunted, and that they must do whatever they can to stop the whaling scheme at all costs.
