In Search of the Titanic (2004)

Tentacolino, or "In Search for the Titanic" tells the story of the familiar characters Juan and Elizabeth, along with their mice friends Top Connors and Ronnie and their bring-along-dog Smile. After the five end up in a submarine accident, they’re taken to the wonderful lost city of Atlantis. There they discover a rebellion of rats who want to break free from the city and take over the world.