Nanaumi Katsuki, an office lady, and Kaede Fujimura, a rookie manga artist, continue their usual cohabitation life. Suddenly, the shadow of a former roommate appears. Although Nanaumi shouldn't have any romantic feelings for Kaede, she finds herself feeling inexplicably uneasy. Meanwhile, she gets closer to Aoi Tsujido, a graceful OL from a business partner. With Aoi's lively conversation, they go from a daytime date to a nighttime date, and before she knows it, they end up at a hotel! Nanaumi begins to realize her true feelings. Then, her junior, Mahiro Koga, who knows about Nanaumi's past, appears... The story takes a dramatic turn in this fourth volume!