Oriol and his friends receive extremely worrying news: the distant island of Tomuku, where the pearl fishers live, is surrounded by plastic waste. The polluted state of the sea means the tomukis can't go diving, puts the turtles' survival at risk and leaves the fish trapped deep under water. The life of the island's inhabitants and the animals who live alongside them is in danger, which is why they've decided to ask for help. The plastic packaging, bottles and bags that are not recycled will end up in the sea, which could end the life of our planet. Without a moment's hesitation, Oriol, Anchovina and Nora set out on a risky journey to help the tomukis.