Kaiki! Drill Otoko no Kyoufu

Three schoolgirls are wandering in the forest, looking for the pension, where they planned to spend the night. However they are stumbling upon a seemingly empty mansion in the middle of the forest instead. Since the sun is about to go down and it's raining anyway, they decide to spend the night there.

However, the Drill Man appears soon after and tries to hunt them down. Will they be able to find out the secret of the mansion? Will they make it out alive? Or will they be captured and kept as playthings for the mysterious inhabitants of the mansion?