Re-Main

 Just after winning a national water polo title in his third year of junior high, a car accident left Minato Kiyomizu in a coma. Nearly a year passes before he awakes, but with no memory of his last school year. Now in high school with a fresh start, he leaves the sport behind, but a promise has him returning to it. However, his new team is weak, and that’s just a sign for more problems to come.

(Source: Funimation)