Full House Kiss

SUZUHARA Mugi is a 15 year-old on a mission. She is determined to somehow get onto the campus of Shoukei high school, one of those super, super elite high schools. This school is huge and private and has tight security. Mugi is searching for her missing sister–her only remaining family–and she has been led to believe that someone or something on the campus of that school will help her in her search. Unfortunately the strict school security is preventing her from getting onto the school grounds.
However, her luck changes when she literally runs into Midou-kun, the son of an insanely rich mega-corporation president, and elite person at the school. Midou is not impressed with Mugi’s sob story about needing to get into that school. He is a very smug and arrogant rich guy. But he can be reasonable, and he eventually strikes up a deal with Mugi–he will get her onto the school grounds in exchange for some labor on her part, that she must come to his house and work as a maid!
Yeah, this is one of those servant-girl stories, but there are a few interesting twists, namely the unexpected way Midou gets Mugi into the school.
— Manga Updates