简介：《Mouse: The Predator》（窥探：捕食者）将从捕食者郑在勋／郑正直(音：郑巴凛)的视角，以顺向时间轴回顾武镇连环杀人事件的始末。制作单位表示：“以第15集为起点，将进入故事新局面，在这之前，为了让大家能理解之前事件中隐藏的叙事，因此制作了两集的番外篇”。番外篇有超过80%内容是正片没有播出的。这两集的番外篇于4月28日16:00(KST)通过网络平台TVING率先播出。
简介：One day, three siblings receive a postcard from their mother who left them a long time ago. But all it says is "I miss you." Three siblings are disconcerted by the sudden contact, but eventually, they go on a trip to meet their mother.
简介：Jihyun is 29 years old and dreams of escaping her hometown of Chuncheon and finding a job in Seoul. On the train ride back home after an interview in the metropolis, she meets a suspicious middle-aged couple, and two stories unfold in Chuncheon.