Meg and Mog - Meg’s Treasure (2003)

Meg, Mog and Owl are out at sea on an island doing some fishing today, and they are having quite a relaxing time too. However, when Meg wonders to herself what it’s like underneath the sea, She and Mog decide to go on an undersea adventure to the depths of the ocean in a fish submarine and while they are in the submarine, they even find a treasure chest, hidden away in a sunken shipwrecked ship. But when they are just about to leave in the submarine, they get an unexpected and frightening surprise....