Monkeys, Yamamoto, and Yamada came to the sea to enjoy a summer aventure. The monkeys are reversed by two cute gal trio and enjoy the first popular period of their lives. The monkeys make friends with one of the gals, Miki, Kaori, and Kyoko, who stay in the same guest house, and make a promise to fireworks together at night. Ritsuko follows the monkeys and comes to the sea, but the monkeys flirt with Miki and bother Ritsuko. Ritsuko who got angry will go home soon. On the way back, Ritsuko went out for a drink with Takase and Uehara who had been picking up, and Mita, a rich man who joined later, liked Ritsuko. Around that time, the monkeys had a nice atmosphere with Miki enjoying the fireworks together.
