Three children force a classmate to a test of courage to get into their group. During the test, which consists in finding a skull in an abandoned church, the child is swallowed by a chasm that opens on the church floor. The other kids, who had stayed out, rush in the church, look in the deep hole, call their friend, but don't receive answers. The little sister of one of them, who followed them, bursts into the church and lets herself down by a rope, but falls into the abyss, dragging the other kids. All five children find themselves into old caves in search of a way out, helped by Grotto, a creature alike a stalagmite.

Three kids force a schoolmate, to a brave test to get into their club. During the test, he fell inside a hole. The other kids think the worst just happen. Since nobody knows about the fact they went there, to go away seems the only solution, to avoid troubles. They don't know that Claire, Luke's sister, has followed them. The girl is allready into the cashm, hanged to a rope. Unluckly, under her weight, the bench starts to move, very fast, and drags the three kids inside the hole. The five kids, inside the cave, have to find a way out. After many vicissitudes, inside one of the most, at the same time, scary and amazing scenary, when everything seems lost, with the very end of their own energy, helped by Grotto, a living stalagmite, they'll find the way out to the caves.