After years of conflict, humans and monsters have settled their differences and are now at peace. This post-war era led to the foundation of Lindworm—a town which has since become the focal point of racial harmony. As a human doctor specializing in monster biology, Glenn Litbeit runs a small clinic alongside his partner, Saphentite Neikes, who is a half-snake monster known as a lamia. He uses his knowledge to tend to any monsters who seek his aid. Whatever affliction, concern, or injury it may be, he will always be there, ready to help.

Rito Yuuki never gets a break—he's always finding himself in lewd accidents with girls around him. Although his heart still yearns for Haruna, his childhood love, Rito can't help but question his feelings for Lala, the alien princess who appeared in front of him and declared she would marry him. But now, it's not just Lala he has to deal with: her younger twin sisters, Momo and Nana, have also traveled to Earth, wanting to meet their older sister's fiancé, and just as luck would have it, they end up staying at Rito's home. Meanwhile, amidst the bustle of his new family members, Yami, the human weapon girl, begins her pursuit for Rito. It's not an easy life for Rito as he deals with uncertain love, punishment for being a pervert, and a girl dead set on murdering him.

Teacher Sorata Muon carries on his family's centuries-old old tradition of being the master thief Mouse who can steal anything after properly alerting authorities of his intentions so they can be there yet fail to stop him. He is assisted by 3 nubile female assistants who also use the teaching cover and who, in typical Satoru Akahori, favor tight/skimpy/bondage outfits over their ample curves as they constantly pursue Sorata much more than he pursues them, although the girls do get some attention from their master. Not only is Mouse pursued by the girls & the local law enforcement authorities, there is also a secret art protection society employing the services of a former ally of Sorata's after his pretty little hide, all in 15 minute episodes.

Shouta Handa is a jobless 25 year old who is sick and tired of his boring life. One evening, at the class reunion, he gets to meet all of the cute girls that used to be his classmates. He soon discovers that they are all successful with interesting careers, and even more importantly—really beautiful now, with bigger curves. Unfortunately, it seems that they are all aware of his boring, unsuccessful life, so they mock him and call him a loser, just like in the old days. Everything changes when Shouta goes for a walk to have a smoke and accidentally falls into the school swimming pool. This triggers a supernatural phenomenon that takes him back ten years into the past. He finds himself in the same swimming pool during swimming class, surrounded by his female classmates in bikinis. How is Shouta going to deal with their cuteness and closeness now that he is a grown man in a boy's body?