Tim is in paradise. Vacationing with his parents, the Raffifis, and Grk in the Seychelles, he is looking forward to two weeks of fun.

But one afternoon, while walking the beach with Grk, Tim stumbles over a body in the sand. Washed up from the ocean and barely alive, the man utters a few words and then dies.

Frantic to help the police discover the cause of the man’s death, Tim and Grk search for clues on their own. But what starts out as a baffling mystery soon becomes a bone-chilling investigation as they encounter armed guards who’ll shoot to kill, a mad scientist’s dream laboratory, and a powerful man determined to live forever, no matter what the cost.

But most puzzling of all is the mysterious Calypso. What is this place? Where is it? And if Tim and Grk venture there alone, will they come back alive?

When he isn’t traveling the world, or writing about Grk, Joshua Doder is a reporter for The Guardian. He lives in London, England.