Hot Gimmick Vol 1

In company-owned rabbit-hutch apartments live tenants who can't afford to live anywhere else. And in the complex where sixteen year old Hatsumi Narita lives, everyone's lives are ruled by the rumor-mongering, self-righteous landlady, Mrs. Tachibana. Get on Tachibana's bad side, and life becomes hell. When Hatsumi has to buy a pregnancy test because her popular sister Akane thinks she's pregnant, Mrs. Tachibana's son, Ryoki, who used to bully Hatsumi as a kid, catches her and promises not to tell the world about Hatsumi's secret as long as she becomes his slave. Suddenly Azusa, Hatsumi's protector in their youth, reappears to save her again! He's moving back into the neighborhood! Despite the budding romance between Hatsumi and Azusa, Ryoki has control over her through the secret that could ruin the lives of everyone in Hatsumi's family, and he hasn't forgotten who his slave is! And he'll make sure Hatsumi doesn't forget either!

Source: Anime News Network Encyclopedia