In a secret place at the end of the world, there's a gigasmic sunken treasure with sparkling jewels and gold doubloons. When the sunlight bounces off it and shines into the sky, it creates dazzling rainbows. In fact that treasure is the source of all the rainbows in the whole world. Betcha didn't know that. Since submarines Olly and Beth are ocean explorers, they set out to find the rainbow treasure, but a whole bunch of bad guys are looking for it too. Like Snarky Sharkskin and his slippery Seahorse Gang. When the treasure's good Sea Lion Guardians turn into evil Sea Lion Pirates, the rainbow is in deep danger. If they steal the treasure, then all the rainbows in the whole world will be lost forever. Oh no. How can Olly and Beth save the rainbow? There's only one way. "Dive, Olly, Dive!" (Source: IMDb)

Octopus Paul was chased by his creditors for owing a huge sum of money. In desperation, he could only take his family and fled to the bottom of the sea, living a life of hiding in Tibet. By chance, Paul met a one-eyed shark (voiced by Tan Mantang). Under the instigation and provocation of the one-eyed shark, Paul actually embarked on the road of gambling. It also became arrogant.

The small submarine Ali went to the depths of the sea to perform a mission and encountered an unprecedented accident. The little shark Meisha refuses to be a submarine king like his father's one-eyed shark, and she dreams of becoming a submarine hero like Ali. The mysterious treasure box she got accidentally changed her father's one-eyed shark back to his childhood appearance. When the treasure box disappeared strangely, a mysterious monster appeared in the underwater playground...