"The mischievous game ends up collapsing their peaceful life. An ordinary housewife In-yeong meets carpenter Hui-su by chance in a café and for fun they decide to become coffee mates: friends who only meet in cafés and nowhere else. Although they don’t make calls or send texts, they can talk to each other about anything while sitting in a café. They share everything, from their daily routines to their deepest secrets, which have never been shared with anyone before. The coffee mates thing started out as a kind of joke but in the end, it shatters the two people’s entire lives, leaving them to face an awful truth they had never been aware of."