In order to pursue her dream of bringing positive changes to Japan, Mitsumi Iwakura leaves her countryside town to attend a prestigious high school in the hustle and bustle of Tokyo. As she has already mapped a clear life plan, she has absolute confidence that there will be zero mishaps from then onwards. Despite her ambitious promise, the country girl ends up running late on the first day when she gets lost on her way to school. Fortunately, she meets a fellow first-year student, Sousuke Shima, who is in the same situation and offers to go with her. They eventually make it to school, but the misfortunes do not end there, as Mitsumi leaves an unfavorable first impression in front of her classmates. Nevertheless, the class soon takes notice of her friendship with Sousuke despite their opposing personalities. Only time will tell whether Mitsumi will be able to forge fruitful relationships with her classmates, and she will certainly not be alone.

All his life, Yuuya Tenjou has been the subject of resentment and contempt from everyone around him, even from his parents. To make matters worse, his grandfather—the only person who ever showed him affection—suddenly dies, leaving Yuuya truly alone. Despite facing many adversities, Yuuya does what he can to offer kindness to those who need it—but even the most good-natured people can only tolerate so much abuse. Just when he reaches his breaking point, a flicker of hope appears in the form of a hidden door in his bathroom. This door provides two-way access to an abandoned house in another world, where he instantly gains game-like stats and skills. Moreover, the house once belonged to a sage, which gives Yuuya access to remarkable weapons, equipment, and crops with extraordinary effects. With these newfound blessings, the once-undesirable Yuuya may just reach his true potential and become unstoppable.

After his first appearance on the competitive world stage, Haruka is held captive by the swimming of the unmistakable champion, Albert, and feels like he's lost his way. With the current state of things, his swimming and what the water means to him are called into question. Haruka begins to sink to the bottom of the murky water as he struggles on his own. Pushed on by a restless urge in his heart, Haruka purposefully puts himself through a rigorous and intensive training regiment, relentlessly devoting himself to practice. In his heart, Haruka knows that he's pushing himself beyond his limits both physically and mentally. His friends can do nothing but watch over and have faith in him. Memories of Albert's cold, dry swimming keep replaying in his mind. I have to get faster, I have to become stronger. I have to compete against Albert again. Haruka unleashes his stroke to cut through the heavy, indifferent water. His friends draw closer to watch. What scenery will Haruka see at the end of this struggle＊──!

Haruka Nanase's new stage is Sydney, the place of his dreams that he once visited. One day while taking a short break before his departure, Haru has a chance confrontation with a fellow athlete from the All-Japan Invitational. Carrying all the feelings from those he's swam with in his heart, Haru takes his first step forward into a new world. Waiting for him there is the unmistakable champion, Albert Volandel. In the lead up to the Sydney tournament, all the competitors attempt to boost their morale. What is each competitor feeling, and what do they swim for, as they attempt to compete at the top of the world? Their passionate struggle against the water begins from here――！