江户川乱步的《地狱的道化师》。李诚与刘月凌准备在初二举办婚礼，除夕这天李诚到刘月凌家吃年夜饭，将父亲李祥勤一人留在家中。李祥勤患有老年痴呆症，夫妇俩怕李祥勤出门走丢，将门窗锁死，导致家中煤气泄露。李祥勤打电话给李诚求救，但李诚在陪老丈人喝酒，未听完李祥勤的话就将电话挂断。A tale of two foster sisters forced to hunt down a wealthy socialite believed to have infected the elder sibling with vampirism.。