Can friendship exist between a man and a woman?! Two 'friends' take on the mission of "If you can masturbate and ejaculate in front of your female friend within 5 minutes, you'll get 30,000 yen!" Seeing the two of them frantically masturbating alone in a closed room... the four girls get turned on! It's a man and a woman after all! Both of them get horny and have sex secretly... and they all end up cumming inside!