It's summer vacation! It's time for free study but Koudai and three girls in his class aren't sure what theme to make for their summer study. Jasmin, the newcomer to the class is full of bravado. "We should study sex!" She proposes. "It's not just to make babies, it feels INCREDIBLY good!" But nobody in the group has had sex before and isn't sex for grown ups? The other girls Akari and Kazumi complain.

How about something else? Koudai proposes. He has a map he found at his grandfather's home listing the location of treasures. If you collect all the treasures for the Supponpon God you get to make a wish! But there's a catch. According to Koudai's grandfather you need to search for the treasures naked! Jasmin, ever full of bravado declares that she can do it. They'll scour the town from east to west each day in broad daylight under the summer sun searching for the treasures to make a wish to the Supponpon God without wearing a stitch of clothing. Is the map real? Is there actually a Supponpon God? Will their wishes be granted? The other girls are too curious to be left out. Later they're joined by another classmate Shizuka, and somehow even their own homeroom teacher Miss Yuuko Kanno and Koudai's older sister Kumi get roped in.

It's a heart pounding naked and sex filled summer adventure!