Daytime in the Bunker 

Seo-U always knew that running away from the son of a murderer would eventually haunt her, but she never expected to be locked underground with him. Years after she abandoned Won-Hyeok following a bloody secret on some stairs, a twist of fate traps them together in the suffocating darkness of an abandoned bunker. As the heavy door clicks shut, Seo-U must decide if the boy she betrayed is here to finally protect her, or if he’s been waiting all these years to exact his revenge. (Source: WEBTOON)