For high school students like Shouichi Kamita, university entrance exams and the future are common concerns. It is also during this time in life that a mysterious emotion that vexes people of all ages may begin to weigh upon one's mind—love. At this point in his teenage years, Shouichi finds three girls he could see himself having a future with: the ever-cheerful Hikari Tsuneki, who teases Shouichi without mercy, but actually has a softer side; the competitive gamer, Tooru Miyamae, who has difficulty communicating with others; and Shouichi's childhood friend, Kyouko Touno, the sometimes immature shoujo manga enthusiast. Seiren follows Shouichi's relationships with these three girls across three separate arcs, as their feelings grow from mutual interest and blossom into something more beautiful.

Kimihara Himeno, also known as "Hime," goes about her life, love, and studies just like any ordinary high school girl. The only difference is that she's a centaur. She enjoys her school life along with classmates of many unique shapes, including Nozomi the draconid, Kyoko the goatfolk, an angelfolk class representative, and Sassas-chan the Antarctican. Hime's younger cousin Shino-chan, her friend Maki-chan, and the class representative's four younger sisters also join the cast in this very cute slice-of-life story about girls who are human, yet aren't!

Nina is a witch who works at one of the street shops of Harajuku. With her magical powers and supernatural abilities, Nina is able to satisfy the needs of her artsy customers. Although, these customers are only allowed to meet Nina when their true desire is well known to her.

Robai Private Academy is a well-known girls’ junior high school in the countryside. Komichi Akebi is a girl who, for a certain reason, has dreamed of wearing a Robai Academy sailor uniform. Her dream comes true, and her heart races as the day of the school entrance ceremony arrives. With her heart set on her new sailor uniform, Komichi embarks on the junior high school life of her dreams. Komichi dashes headlong through days full of “firsts”—classmates, school lunches, club activities, and more—in this sparkling diary of girlhood. “I hope I can make a lot of friends.”

Yayoi Sakamoto, a diehard fan of comedians and comedy acts, enrolls in the private Kazuki High School in Nanba (Osaka's entertainment district famous as the starting point for many comedians). She reunites with Yomogi Takahashi, a childhood friend who once formed the comedy duo "Konamonzu" with her when they were little. Before long, they find themselves putting together a routine at a park like they did before, in order to enter a local shopping area's contest. At that moment, a mysterious girl calls out to them.

The story begins 15 years after the demon king was defeated and the world has become peaceful. Kotone, who graduated from school and became a magician, inquired the kingdom-affiliated RPG Real Estate in order to find a new home. In reality, RPG Real Estate was Kotone's place of employment, and together with Fa, a demi-human, the priest Rufuria, and the soldier Rakira, they help support the searches of new homes for the customers with various circumstances.

High school student Michio Kaga was wandering aimlessly through life and the Internet, when he finds himself transported from a shady website to a fantasy world — reborn as a strong man who can use "cheat" powers. He uses his powers to become an adventurer, earn money, and get the right to claim girls that have idol-level beauty to form his very own harem.

Hitori Bocchi, a girl with extreme social anxiety, has had only one friend throughout elementary school. When Bocchi learns they'll be split up after graduation, she makes a promise to her: "By the time of my middle school graduation, I'll make friends with everyone in my class." And if she can't... they won't be friends anymore?! But Bocchi has a hard time talking to people. When she gets nervous, her legs cramp. She can't look other people in the eye. She doesn't even know how to make friends! Every way she thinks of to make friends ends up failing. Will her friend-making plan pay off?!

Hitori Bocchi, a girl with extreme social anxiety, has had only one friend throughout elementary school. When Bocchi learns they'll be split up after graduation, she makes a promise to her: "By the time of my middle school graduation, I'll make friends with everyone in my class." And if she can't... they won't be friends anymore?! But Bocchi has a hard time talking to people. When she gets nervous, her legs cramp. She can't look other people in the eye. She doesn't even know how to make friends! Every way she thinks of to make friends ends up failing. Will her friend-making plan pay off?!

Hitori Bocchi, a girl with extreme social anxiety, has had only one friend throughout elementary school. When Bocchi learns they'll be split up after graduation, she makes a promise to her: "By the time of my middle school graduation, I'll make friends with everyone in my class." And if she can't... they won't be friends anymore?! But Bocchi has a hard time talking to people. When she gets nervous, her legs cramp. She can't look other people in the eye. She doesn't even know how to make friends! Every way she thinks of to make friends ends up failing. Will her friend-making plan pay off?!

Kiyo and Sumire came to Kyoto from Aomori Prefecture, dreaming of becoming maiko. But after an unexpected turn of events, Kiyo starts working as the live-in cook at the Maiko House. Their story unfolds in Kagai, the Geiko and maiko district in Kyoto, alongside their housemate maikos. Kiyo nourishes them daily with her homecooked meals, and Sumire strives toward her promising future as the once-in-a-century maiko.

One day, Naho Takamiya receives a letter written to herself from ten years in the future. As Naho reads on, the letter recites the exact events of the day, including the transfer of a new student into her class named Kakeru Naruse. The Naho from ten years later repeatedly states that she has many regrets, and she wants to fix these by making sure the Naho from the past can make the right decisions—especially regarding Kakeru. What's more shocking is that she discovers that ten years later, Kakeru will no longer be with them. Future Naho asks her to watch over him closely.

One day, Naho Takamiya receives a letter written to herself from ten years in the future. As Naho reads on, the letter recites the exact events of the day, including the transfer of a new student into her class named Kakeru Naruse. The Naho from ten years later repeatedly states that she has many regrets, and she wants to fix these by making sure the Naho from the past can make the right decisions—especially regarding Kakeru. What's more shocking is that she discovers that ten years later, Kakeru will no longer be with them. Future Naho asks her to watch over him closely.

Awakening from magical stasis after a thousand years, the Dark Lord Leonis suddenly finds himself in the body of a ten-year-old boy! He quickly meets Riselia, a girl confronting the Voids, creatures that have nearly exterminated humanity. Determined to uncover the mysteries of this strange new era, Leonis enrolls in Excalibur Academy, a school that trains students to fight back against these enigmatic monsters. Could the Voids hold some connection to Leonis's past?