While searching for the secret of opening and closing the door of Dongdong City, the transforming octopus finds out that the key to opening the door of Dongdong City is Beluga's song. Rojo orders the transforming octopus to kidnap Beluga. The octopus who went to Dongdong city to kidnap Beluga is ...

Dr.Turtle and Rojo, the villain of the sea, were friends who played and studied together as children. Dr.Turtle designed Dongdong City that moves under the sea, and dreams of a happy sea world. However, Rojo is twisted because of his jealousy of Dr. Turtle and his desire to take over the sea. Roj...

The hobby of Brave Monodon, who always enjoys adventure, is 'Riding a dangerous current. Today, monodon, which has been hit by a strong and urgent current, has fallen into a whirlpool. Due to the large vortex, the monodon is quickly swept away in a terrifying place."

The transforming octopus spreads rumors that the sea's kelp forest died and a desert was created because of friends in Dongdong City. Angry sea friends shout "Dongdong city, leave and disappear" here and there.

It was Rojo, the villain of the sea, who kidnapped Kakarot for the deep sea map. The entire ocean world could be in danger if the deep sea map falls into the hands of the villain Rojo. Dr. Turtle and the Sea Five Musketeers are going to save Kakarot and the Deep Sea Map...

Deep, dark, dangerous sea, The Deep Sea. Kakarot, the sperm whale, goes exploring to make a deep sea map for his sea friends. Kakarot informs Dr. Turtle that the map has been completed through a video call. Then, suddenly, the video call is cut off with Kakarot's scream. Kakarot is in danger beca...

The moving day of Dongdong City. Monodon, the Unicorn Whale, goes to say goodbye to friends, hung out with.
But... Oh, no! Monodon's horns are tied to the seaweed forest.
The time to move away is approaching, and Monodon tries to untie the seaweed caught in his horns in a hurry, but it gets tied ...

Dongdong City is moving because the current has changed! While Beluga, the White whale was moving her favorite treasure jar, she missed it with a strong current. Boto the pink dolphin that was helping Beluga is trapped in an upside-down treasure jar. There's not enough air in the jar, so it's get...

The day of the Dongdongseong concert. With a jar of treasure, Beluga on stage sings a beautiful song. A group of Orca, a group of killer whales, breaks the stage and steals a glass jar...

Boto, Bao and their friends, who meet a rock monster during a hide-and-seek game, are surprised and run around. By the way, the rock monster was a new friend, coming to Dongdong-City, "Yan, the gray whale". Boto, Bao and their friends,, who didn't recognize their friends, apologized to "Yan, the ...