Molester Bus: The Back Door Is Okay Too (1987)

Nancy and Cathy, although unaware of each other’s pasts, are very close friends working as seductive sex workers. Every day they become so absorbed in playing games at the game center that they end up being late for work. Their workplace is a mobile adult entertainment establishment—a dilapidated bus that has been remodeled to cruise through the neon-lit streets of Shinjuku at night. Inside, as the two alluring women cling onto suspension straps and completely surrender their bodies, the men, transformed into vicious lecherous molesters, give in to their intense lustful impulses and ravenously indulge in a serious sexual crazed experience. Then one day, Cathy is killed by one of the vicious customers...