Instructor Oni-Hige is seen of harassing a woman in the Roppongi district, and is beaten up by George, her huge American boyfriend. For revenge, Oni-Hige then sends the students on a purifying mission in the Roppongi district against dominating foreign men. They find the huge American in a discotheque, but the students find excuses not to fight him, and Oni-Hige is beaten up again. The next day, instructor Rankiryuu orders Hidemaro Genzo who is now a student, to purchase make-up in Roppongi. Meanwhile, the students are punished by having to hold a handstand position for an hour. Hidemaro sees the Americans scamming a local shop assistant and confronts the former WBB heavyweight boxing champion J.J. George but is easily beaten up. The students decide to take revenge, and using a combination of karate and kenpo, Momotaro beats him up. When Yoko, George's Japanese girlfriend, abandons him and approaches Momotaro, he rejects her for being fickle.

Note: When Togashi is instructed to translate Japanese in the discotheque, he just shouts some common English phrases that he knows.