Naho Takamiya's first day of her sophomore year of high school is off to an uneasy start. After waking up late, she receives a strange letter addressed to her. However, the letter is from herself—10 years in the future! At first, Naho is skeptical of the note; yet, after witnessing several events described to take place, she realizes the letter really is from her 26-year-old self. The note details that Naho's future life is filled with regrets, and she hopes that her younger self can correct the mistakes that were made in the past. The letter also warns her to keep a close eye on the new transfer student, Kakeru Naruse. Naho must be especially careful in making decisions involving him, as Kakeru is not around in the future. With the letter as her guide, Naho now has the power to protect Kakeru before she comes to regret it once more. [Written by MAL Rewrite]

On his way home from school, Tatsumi sees a man collapsed near a lake. When he approaches him, Tatsumi notices something strange: the person in need of help is actually a beautiful merman named Wakasa! Because Wakasa's home has become too polluted to live in, Tatsumi graciously offers his bathtub as a refuge. With a boisterous merman as his new roommate, Tatsumi's normal life won't be returning anytime soon, not to mention Wakasa's aquatic friends—Takasu, Mikuni, and Maki—often show up uninvited, making them all quite a handful for the high school student. As he humors their curiosity for human life, Tatsumi sometimes finds himself enjoying their childish antics, but he will have to keep his cool if he intends to keep up with his daily life and newfound friendship. [Written by MAL Rewrite]

Miou Aida and Haruki Serizawa might seem like polar opposites to those around them, but as the two third-years prepare to end their high school experience, they couldn't have been been closer. While Miou is a shy and reserved member of the school art club that prefers to stay out of the limelight, Haruki is the boisterous and confident ace of the movie club, already winning awards for his directing prowess. However, after a previous chance encounter during their school entrance ceremony, they quickly become friends despite their stark differences in personality. But although their closeness might be growing, they've never become anything more than just that, much to the bewilderment of their friends. As their time in high school draws to a close, Miou and Haruki, along with their friends in the art and movie clubs, have just one year left to face their hidden feelings and the daunting task of deciding their future careers. The two might always be only an arm's reach away, but as Haruki chases his dream of becoming a professional movie director and Miou struggles with choosing a path for herself, they'll learn just how hard it is to get past those last 10 centimeters. [Written by MAL Rewrite]

Eighteen-year-old Dale Reki is a skilled, kind, and respected traveller, acknowledged as one of the leading adventurers in the city of Kreuz. One day while on the hunt for magical beasts, he comes across a sweet devil girl named Latina. She is alone, dressed in rags, and bears the devils' symbol of a criminal: a broken horn. Concerned for her wellbeing, Dale decides to ensure Latina's safety by bringing her to his home, eventually leading to him adopting her. Latina is sweet, innocent and compassionate, charming Dale beyond his expectations. He begins to enjoy the life of parenthood— experiencing the trials that come with raising a child and coping with the heartache he feels whenever his busy lifestyle as an adventurer parts him from her. Although work and life as a new parent become reassuring constants for Dale, the mysteries surrounding the girl remain. Why was Latina alone in the forest, and why does she harbor the symbol of a criminal? At the same time, Latina also begins to learn about the world and herself as she adjusts to her new life with Dale. [Written by MAL Rewrite]