Awaking to absolute chaos and carnage while on a school trip, Yogiri Takatou discovers that everyone in his class has been transported to another world! He had somehow managed to sleep through the entire ordeal himself, missing out on the Gift — powers bestowed upon the others by a mysterious Sage who appeared to transport them. Even worse, he and another classmate were ruthlessly abandoned by their friends, left as bait to distract a nearby dragon. Although not terribly bothered by the thought of dying, he reluctantly decides to protect his lone companion. After all, a lowly Level 1000 monster doesn't stand a chance against his secret power to invoke Instant Death with a single thought! If he can stay awake long enough to bother using it, that is...

When you look up at the sky, what do you see? A blue sky? Freedom? A hopeful future? The people of Tokyo see none of these. Instead, an ominous alien mothership looms overhead, engulfing the city skyscape. Three years ago, they came. The arrival of the "Invaders" sparked the greatest war humanity had ever faced—one that threatened to end the world. The Japanese government scrambled to fight the Invaders. Weapons were mass-produced, sparking controversy and pacifist movements. That day, everything changed. And yet, nothing has changed. Kadode Koyama and Ouran Nakagawa live their final days like they always have: going to school, playing with friends, and doing what any carefree high school girl would do. As they grow up, they come to learn what it truly means to be an adult, in a world where adults seem to be demons who only deceive and destroy. They come to learn the real threat to humanity is not the Invaders, but humanity itself.

In front of a camera, roommates Mao Tsuchiya and Hisashi Ootomo make three promises: Mao must not tell anyone Hisashi is gay and in a relationship with another man; Hisashi must never fall in love or make any advances on Mao; and one must not disturb the other's "personal time." Thus begins their second year of cohabitation. However, everything starts to crumble when the film club—of which Mao is a member—wants to cast Hisashi in the lead role for their upcoming movie. The problem arises with the movie's plot, as it is about boys' love—a romance between a delinquent and the class president. Mao is adamant to dissuade Hisashi from becoming the protagonist due to their first promise; but, to his surprise, Hisashi is easily convinced by the director. After imagining Hisashi as the delinquent he is playing, Mao becomes overly conscious of his presence. He knows Hisashi is just a friend and out of his reach, but Mao cannot keep lying to himself anymore—his feelings toward his roommate may no longer be purely platonic.

Smart, refined, and strikingly gorgeous, half-Russian half-Japanese Alisa Mikhailovna Kujou is considered the idol of her school. With her long silver hair, mesmerizing blue eyes, and exceptionally fair skin, she has captured the hearts of countless male students while being highly admired by all others. Even so, due to her seemingly unapproachable persona, everyone remains wary around the near-flawless girl. One of the few exceptions is Alisa's benchmate Masachika Kuze, a relatively average boy who spends his days watching anime and playing gacha games. Despite his nonchalant demeanor, Masachika is the sole student to receive Alisa's attention. Unable to be fully honest, Alisa is frequently harsh on Masachika and only expresses her affection in Russian. Unbeknownst to her, however, Masachika actually understands the language yet simply pretends otherwise for his own amusement. As the odd pair continues to exchange witty and playful remarks, their relationship gradually grows more romantic and delightful—and Alisa might finally learn to freely convey her true feelings.