In Costarica, in the province of Sarapiqui, north of San Josè, the scientist Donald Ray Perry, studies the hollow trees in the tropical forest. Their hollow trunks looks like an empty shells but the trees continue to grow and rubs and animal droppings acumulate inside them which attracts many insects. The scientist climbs down the hollow, almost like a potholer, to analyze the strange microcosm that exist in it.