Philya the simpleton, Danya and twin sisters Aska and Anya come with their parents to the resort town of Koktebel. And the adventure begins! Friends immediately find themselves in a “stone trap” on Mount Chameleon. Did this happen by chance, or were the guys lured there by a suspicious character whom they nicknamed the Gray Cardinal? To find out, the inseparable four have to fight a chameleon man - the guy who stole a stone that brings good luck from the museum. The scammer is dragging the famous singer Prikolov into his machinations, so you can’t just get close to him. But the Simpleton and his friends are not discouraged - after all, they have unraveled more complicated cases...