After surviving a brutal terrorist attack on Plant Quetta, Suletta Mercury returns to dueling at the Asticassia School of Technology, while Miorine Rembran sits at her injured father's side, waiting to see if he will recover. As the residents of Earth House are preoccupied with their respective troubles, two members of Dawn of Fold—the perpetrators of the attack—secretly infiltrate the school, putting Suletta and her friends at risk. At the same time, Prospera, Suletta's mother, approaches Miorine to propose the continuation of Quiet Zero—a project headed by Miorine's father that can allegedly end all war. Prospera seems to be another political figure with hidden, opposing motives, and whether she truly has Suletta's well-being at heart remains to be seen.

Gorou Honda, a little boy obsessed with baseball, has always admired his father, Shigeharu. Wishing to follow in his father's footsteps, Gorou dreams of becoming a professional baseball player. In turn, his son's starry-eyed admiration encourages Shigeharu to keep persevering, despite his late wife's death and his unsatisfying position on the second-string team Blue Ocean. Unfortunately, an elbow injury forces Shigeharu off the team, and he falls into despair. However, after an offhand joke from his childhood friend, Shigeharu reevaluates his choices and decides to keep playing, leaving behind his prime position as pitcher and taking up the bat. Now motivated more than ever, Gorou works hard to carve his way in the Japanese Little League.

When Minato Kiyomizu wakes up in a hospital, he learns that he has been comatose for 203 days. As it turns out, a car accident has caused him to lose all memory of his middle school journey. Eventually, he discovers his former glory in water polo and desires to continue where he has left off. However, embarrassingly becoming aware of the massive disparity between his old and current self, Minato begins intensive rehabilitation in hopes of starting anew—a life without water polo. Yet, Minato is promptly reminded of his past prowess and a promise on his very first day in Yamanami High School. Soon enough, despite being completely aware of his ineptitude, he joins the school's water polo club! While needing to relearn the sport's basics, he, along with his clubmates, must recruit new members to attain the required seven-man roster. With that, Minato tries to rekindle his deeply buried talent for water polo—and become one of Japan's renowned players once again.

Naoya Mukai's crazy lifestyle of balancing his time between both of his girlfriends, Saki Saki and Nagisa Minase, is still as hectic as ever. Additionally, the blonde bombshell Rika Hoshizaki also has her sights on Naoya, complicating his already convoluted love life. As if things could not get more ridiculous, another girl inserts herself into the situation: Shino Kiryuu, who is determined to end Naoya's two-timing and ensure Saki's happiness. However, Shino harbors secret feelings for Naoya—a longing she believes she must forsake—yet simply cannot due to the deep attraction he inspires.