Hermy lives happily on the beautiful ocean floor. Today, he decides to look for a secret hideout!
As he searches with his friends, Shelly and Breamy, they discover a sparkling blue and beautiful cave!

“Alright! Let’s make this our secret hideout!”

Time flies by as they have fun.
The surroundings turn crimson with the setting sun, and it’s time to go home. However, they cannot leave the secret hideout. The sea water has receded, making it impossible to reach the entrance. What a dilemma! The sea water continues to decrease. If this keeps up, Breamy will be in great trouble.
How will Hermy and his friends overcome this crisis?