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.

When Santa's helper La Befana falls ill and must take off a Christmas Eve, she recruits Scarafoni to help deliver all the toys. No one but the toys knows is that Scarafoni plans to auction off the toys to the highest bidder, which means the toys won't make it to the children who have been good all year and deserve them. The toys decide to deliver themselves, and the story follows them as they struggle to avoid the heartless Scarafoni and to find their true homes.