When twin brothers Trevor and Kyle Ritland were children, their father — a biologist — would tell them stories about a mythical creature that lived high in the misty mountains of Costa Rica: the golden toad. The toad was elusive, he told them — but for a few weeks every spring, hundreds of them would emerge from the shadows to mate, lighting up the dense forest like brilliant spots of fire. Until one day, the golden toad vanished — never to be seen again.