Masuda Suzu is a researcher at a health food company who has excellent observation skills and loves the 2D world (manga, anime, and video games). She has no interest in real-life romance but somehow becomes attracted to the new resident Katori Shun. With his communication skill and refreshing smile, Katori easily finds a way into people's hearts. However, Suzu does not understand why Katori could not move on after his confession to Itsuka got rejected. Taking the opportunity of living together under one roof, Suzu decided to observe Katori as her newest research subject. What is the real side of Katori that Suzu will witness?