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.

Second season of Osomatsu-san.

Despite his noble title, Noir Stalgia is at the bottom of the social hierarchy. Because of this, his fellow nobles oppress him and treat him like garbage. However, he possesses a rare yet powerful ability to communicate with the Great Sage, an oracle who grants Noir the answer to absolutely anything. After failing to secure a job as a librarian, Noir decides to join the Hero Academy. He knows he must become stronger to enter the institution. The Great Sage advises him to explore a hidden dungeon deep within the mountains. There, Noir meets Olivia Servant, a beautiful yet enchained maiden trapped within the labyrinth. Olivia bestows upon Noir a set of ridiculously powerful skills that grants him virtually total control over reality. Naturally, there is a catch—every time Noir attempts to use his powers, his life points decrease, putting his life at risk. To replenish his energy, he must give in to worldly pleasures such as kissing his childhood friend! With his newfound powers, Noir begins his journey as a student in the Hero Academy, meeting new acquaintances and helping them through the dire situations ahead.

Aspiring light novel author Yuu Nagami regularly enters writing competitions but has yet to win a single one. Despite his recurring failures, he remains steadfast in his resolve to become a better writer. When he takes a look at the list of winning authors in the latest contest he joined, he notices that someone named Chikai Towano dominated the competition. He soon discovers that behind the pen name is his sister Suzuka—the last person he can imagine being an author. Suzuka cannot reveal to anyone that she is Chikai Towano and requests her brother to take her place. Yuu agrees with one condition: he will continue posing as Chikai Towano for his sister until he publishes his own book. Until that happens, Yuu uses his new identity as an opportunity to improve his writing skills and meet fellow authors and new acquaintances along the way.