Rex, the adventurous dog, heard about a lost dog race under the sea and wanted to join. He put on his scuba gear and dove into the deep blue sea.

Under the sea, Rex met a friendly octopus named Oliver who offered to help him find the lost dog race. They swam past colorful coral and playful fish.

Suddenly, a mischievous shark appeared, blocking their path. But Rex bravely barked, scaring the shark away. With the shark gone, they continued their journey.

After a while, they came across a group of sea turtles who knew the way to the lost dog race. The turtles led them through a maze of seaweed and sunken ships.

They finally arrived at a beautiful underwater city where the lost dog race was being held. Rex spotted his friend Max among the contestants and joined the race.

The race was filled with twists and turns, but Rex and Max worked together, using their cleverness to navigate the challenges. In the end, they crossed the finish line first, winning the race!

With the race won, Rex and Max were celebrated as heroes of the undersea world. They received shiny medals and made new friends. Rex realized that adventures under the sea could be just as fun as on land.