For high schoolers like Shouichi Kamita, university entrance exams and the future are typical worries. It is also during this stage of life that a mysterious emotion, which troubles people of all ages, may start to occupy one's thoughts—love. At this point in his adolescence, Shouichi encounters three girls he could envision a future with: the perpetually cheerful Hikari Tsuneki, who mercilessly teases Shouichi but actually possesses a gentler side; the competitive gamer Tooru Miyamae, who struggles to communicate with others; and Shouichi's childhood friend, Kyouko Touno, an occasionally immature shoujo manga fan. Seiren follows Shouichi's relationships with these three girls across three distinct arcs, as their feelings evolve from mutual interest and bloom into something more beautiful.