Johnny is a young seahorse architect who lives in the Pacific Ocean. Although he is small, he has a huge heart that can hold all the oceans of the world. But his biggest dream is to find out what happened to Pearlville and build the first pearl apartment building underwater with magical pearls.

So, Johnny, along with his crew, the Johnobakaliaris, embarks on his journey to the mythical Pearlville. There, he will encounter confusing situations - languages that speak more than their size, and many glowing fish that shine brighter than their own light - with the danger of his plans being destroyed.

However, a team of underwater conquerors created by Johnny will do their best, with the common goal of creating the pearl apartment building. Will the conquerors succeed?