Mr. Kim has never been supportive of his daughter joining the police force, hence, putting a strain in their once close relationship. However, when he starts to receive death threats in the form of letters covered in dried blood, Sojung can't just sit back and do nothing. This might be the chance for her to prove her father that her decision to join the police force wasn't a mistake.

However, she knows it wouldn't be easy to find the culprit and somehow, she thinks her next door neighbour knows something relating to the case.