They were Best Friends Forever. However, this relationship starts swaying when Jaewon finds out what his friend is actually thinking of him..

Original Webtoon

Official Translations:
English

‘Whatever, Geezer.’
Jaewon was insulted by his neighbor who was smoking a cigarette. He swore that if he encountered her again, he would kill her. That girl turns out to be a new part-time worker at his company. She’s even his best friend’s girlfriend? What’s going on?