A devil-girl with the face of an angel and a heart of gold, blond Betty falls in love with an earthbound gangster, Danpei Kimogawa, when they meet in a rainstorm. They end up living together in a Tokyo highrise apartment, though Danpei has trouble coping with his new witch and demon in-laws dropping in at inopportune moments. Betty has actually been sent to the human world on a mission to defeat the demon Lutan. While Betty continues her task, her skeletal grandmother sends nubile nymphs to tempt Danpei and see if he is suitable husband material.

The Underground People desire to leave their overcrowded cavern and seize control of the surface world, but they never quite succeed. A second episode, Christmas Aid, soon followed, in which the brainless Undergrounders' second futile escape attempt is set to music by the popular group Yukadan. The first volume also included two unrelated stories by Ishii: 101 Ninja and Ken-chan's Space Exploration Adventure.

Based on the manga by Big Joe (ビッグ錠).