Kō Kitamura, whose family owns a sporting goods store, has known the Tsukishima girls since he was born. The Tsukishima family runs a batting center and cafe, and they have four daughters. There's Ichiyo, the responsible eldest; Wakaba, Kō's cheerful best friend; Aoba, who doesn't get along with Kō; and Momiji, the energetic youngest daughter. When Kō enters high school, he aspires to lead his baseball team to the Koshien National High School Championship as their ace pitcher and make Wakaba's dream come true.

The story is set in a world embroiled by war between Humans and Demons. The Humans’ greatest hero invades the Demon Queen’s castle determined to vanquish her. However, instead of fighting back, the Queen proposes an alliance with the Hero. She explains how a sudden end to the war can bring further chaos to the world as the Humans once united to stand against their common enemies would eventually begin fighting among themselves, with similar issues already occurring at the Demon Realm. Convinced by her words, the Hero joins forces with the Queen and together they execute a plan to bring prosperity and a lasting peace to both Humans and Demons alike.

The girls in a high school literature club do a little icebreaker to get to know each other: answering the question, "What's one thing you want to do before you die?" One of the girls blurts out, "Sex." Little do they know, the whirlwind unleashed by that word pushes each of these girls, with different backgrounds and personalities, onto their own clumsy, funny, painful, and emotional paths toward adulthood.

After being in a coma for 17 years, Takafumi's middle-aged uncle suddenly wakes up speaking an unrecognizable language and wielding magical powers.

Ganta Nakami is a high school student who suffers from insomnia. He meets Isaki Magari, a girl with the same condition. A relationship forms as they share a secret and catch up on their sleep in their school’s abandoned observatory.