Minato Kiyomizu wakes from a coma following a car accident. Though once a water polo star in junior high, he's lost three whole years of memories. Abandoning any hope of playing again, he enters Yamanami High School an entire year late.

Minato learns from Chinu Kawakubo about a promise they made in the past. To fulfill their promise, he decides to join the water polo club, much to the delight of Eitaro Oka and the team captain, Jo Jojima. They utilize his fame to recruit members, but...

Takekazu Ejiri, Yutaka Babayaro Inomata, and Yoshiharu Ushimado join the club, but it needs one last person to make seven for a regulation team. They ask Shugo Amihama, who swam in junior high, but he refuses. When they persist, Shugo makes a proposal.

Though they're only up against a junior team, the club learns just how intense water polo, aka "water wrestling," can be. Minato's spirits are crushed by his own uselessness, but that night, Eitaro pays a visit and reveals a big secret he's been hiding.

Jo, the water polo captain, proposes that the team creates an original jersey. But emotionally attached to his own, Amihama declines saying, "I don't need a jersey."

It's finally time for their second match of prefecturals--the long-awaited showdown with Shogakukan. Minato, Eitaro, Jo, Amihama, Ejiri, Babayaro, and Ushimado join their seven hearts as one and challenge the best team in Japan.