In the days of the Mayas, cenotes – deep, natural pits on the Yucatan peninsula - provided the only means of obtaining drinking water. But in the mythology of this advanced civilisation, these waterholes and caves were also the entrance to Xibalba – the underworld.

The greatest adventure of his life begins for Checker Tobi on a pirate ship in the middle of the sea. There he discovers a message in a bottle containing a riddle. If he solves it, he will reveal the secret of our planet. An exciting scavenger hunt around the world begins! Tobi climbs the crater of a fire-breathing volcano, dives with sea dragons in the Pacific, explores the loneliest parts of the Arctic with climate researchers and ends up in India at the driest time of the year. In Mumbai, he becomes a Bollywood star before the monsoon transforms the megacity. Tobi finally realizes that he had the solution to the puzzle in mind throughout his journey.

Tuna are among the top predators in the oceans. But the hunter is also the hunted: many species are overfished. Can we use the riches of the oceans without destroying them?