A group of 10 true crime obsessives are invited to the opening weekend of the newly renovated Cold River Motel, the site of a 30-year-old unsolved satanic mass murder. History repeats itself when the guests get stranded and start getting knocked off one by one during a murder spree that grows exponentially more gruesome than the original with each kill.

讲述了被小说中的配角附身的主人公后，无意中与男主人公共度一夜而展开的惊险浪漫故事。

本剧讲述了浅草的75岁老太太松子（“终极大魔王奶奶”）在失业后不服老，创办便利屋，与个性各异的年轻人住进同一个合租屋，展开第二次青春。面对客户的各种烦恼，她用天马行空又真诚的方式解决问题，也在过程中反思孤独与人生意义。合租屋里，有迷茫的公务员、视频博主、人力车夫、外国留学生等，他们也在与松子的相处中逐渐改变。这是一个跨世代相互治愈的温暖喜剧。