Season 1

It is 2019 and aliens have nearly annihilated the human race with their powerful abilities to transform. As humanity faces extinction, the aliens settle on Earth and even fully embrace human culture by living like humans once did. Today, it is alien student Yohei's turn to feed the two chickens kept at his school. However, unbeknownst to him, those two chickens are hiding a surprising secret.

Sasaki's heart beats faster every time he looks at Kawaguchi sensei. He puts her on such a high pedestal that he even reveres her as a goddess. As he is attending supplementary lessons over spring break just to see her, an armed man bursts into the classroom. Holding the students hostage at gunpoint, the man makes a selfish demand of Kawaguchi sensei, but Sasaki jumps right in front of the gun.

Ibuki makes a big decision on the eve of his graduation and invites Yuri to walk home with him. Since he will attend college abroad, this will be the last time he will see her. Determined to confess his long-standing love for her, he gathers his courage, only to be interrupted by dire situations. However, those are the least of his priorities right now.

After a childhood of abuse, Shikaku is now an infamous assassin. She gets hired by Yugeru, a 3,500-year-old vampire, to end his tiresome and boring life. However, not even Shikaku was able to fulfill his wish. Upon returning home, Shikaku finds herself unable to stop thinking about Yugeru as unfamiliar emotions torment her heart.

Toshihide's greatest treasure is an abandoned underwater piano. Playing it allows him to feel connected to his mermaid mother. One day, he meets the mermaid Shiju. She has been secretly listening to his performances and happens to save his life. When he offers to teach her the piano, they soon become good friends. However, mermaids are terrifying creatures that feed on human beings.

Toshihide wakes up one day and learns he has a very rare and incurable disease. Now that he has turned into a beautiful girl, he becomes the target of the boys' harassment. When Akira, his girlfriend's brother, comes to his rescue, Toshihide realizes he might be attracted to Akira. In this confusing situation, Toshihide and his girlfriend must decide what will become of their relationship.

Kenji's little sister, Nayuta, has horns on her head, cannot speak properly, kills animals, eats their carcasses, and is generally abhorred by everyone. After all, she is prophesied to destroy the world. However, she is his only family and he vows to do his best to protect her. He has been managing well until Nayuta incurs the people's wrath with her actions.

Walking into school one morning, Mitsuko is shocked to see a humiliating painting of her! It was painted by her little sister Kyoko and since it won the art contest, the painting will be displayed for the entire year. Vowing to avenge this, Mitsuko decides to shame her sister in the same way. As she works on her painting, Mitsuko reminisces about her strained relationship with her sister.