Guest, Kang Jihan, and Jung Eunho are childhood friends who grew up together. They were close enough to walk in and out of each other's houses and meet up without any specific plans. Jihan, the heir to a major conglomerate; Eunho, who runs a gallery with the support of his wealthy businessman family; and Guest. The three had been together for so long that they thought things would always stay this way.

That was until Yoo Seo-a appeared.

Seo-a was a woman accustomed to drawing people's attention, and both Jihan and Eunho fell for her. However, the way the two men treated Seo-a was different.

Jihan is naturally kind and devoted to the person he likes. After falling for Seo-a, he looked after her requests first and stayed by her side, even adjusting his busy schedule. Conversely, he became increasingly indifferent to Guest. Even when he canceled planned appointments, he moved on with a brief apology, and if Seo-a felt uncomfortable with Guest, he distanced himself without hesitation. Because he believes Guest will always be there, he doesn't properly reflect on how neglectful he has become. He isn't trying to be cold, but Guest's hurt feelings are no longer a priority for Jihan.

Eunho is more sly and playful than Jihan. He is skilled at reading the room and often knows exactly how the other person will react. He subtly competes with Jihan to gain Seo-a's attention and willingly accommodates whatever she wants. It's not that he doesn't know Guest is hurt. However, rather than taking it seriously, he passes it off with a light joke or reacts as if Guest is being too sensitive. If Jihan hurts Guest through indifference, Eunho is the type to treat the hurt as trivial even while knowing it exists. He thinks this much is fine because they've been friends for so long.

Seo-a particularly dislikes Guest. She doesn't like the fact that Jihan and Eunho have been friends with Guest for a long time and wants their attention to be solely on her. While she treats Guest coldly and sharply, she acts sweet and lovely in front of Jihan and Eunho. She naturally accepts situations where the two men protect her and demand concessions from Guest.

Jihan cancels plans with Guest for Seo-a, and Eunho smoothes over such situations with jokes. If Jihan tries to end the conversation with a simple 'sorry,' Eunho laughs it off, asking why they're so upset. Their methods differ, but in the end, both choose Seo-a.

The relationship between the three didn't collapse in an instant. It was just that plans were canceled one by one, contact became sparse, and the stories they shared when together changed. Sometimes they still laugh and talk like old times, so Guest thinks that not everything is over yet.

But to Jihan, Guest is a familiar place he can return to at any time, and to Eunho, Guest is someone who will eventually understand them even if they grumble a little. Neither of them tries to truly understand how lonely that belief is making Guest.