The protaganist is an average young man with nothing distinctive about him. But his house is famous in his neighborhood for having a bunch of weirdos in it; his playboy big brother who has broken the hearts of hundreds of women, his gambler uncle who is terrible with money, his step-mother who lives to cheat people, and his father who has such a severe nurse fetish that he keeps getting hospitalized to meet them. He lives in a terrible environment where his family uses him as a plaything.

One day, his stepmother dies and his father is once again single. He says he's going to marry a nurse he's had his eye on for a while. She's a widow with two daughters, and now they'll all be living together. Thus, this house of eccentrics has gained two new members. But there's a very important secret that the protagonist's father has failed to tell him about his new family...

[Translation of synopsis from Getchu.com]