Childhood friends Ginu and Yubin live in separate apartments in separate buildings right next to each other – so close, in fact, they can talk to each other and see into each other’s apartments through their windows. But Yubin’s long-held secret is revealed one day when Ginu sees him doing something naughty through the window...

(Source: Lezhin US)

Note: The manhwa resumed publication in 2020 on Bomtoon with a series of side stories.