Deep under the earth's surface dwells a beast that is only known to a select few. Currently docile, the beast is appeased by playing with the bodies of girls who indulge all its appendages. It's Eri's first day at her new job in the Chamber of the Demon Lord, and as she tags out one of her new co-workers, Maruka, the beast wraps them both up to see what this new girl is made of.