This book tells the ending of a serial case from the perspectives of criminal police, hotel staff and victims, highlighting the necessity of legality and morality. After investigating a series of cases, the police found that the deceased in the three cases all had criminal histories and were suspected of seeking revenge for the bereaved families. The surviving family members all checked into the hotel on the same day, which attracted the attention of the police, who began an undercover investigation and tried to prevent the fourth case from happening. While working undercover in a hotel, detective Nitta encounters Miwa, an old classmate and former court prosecutor. He discovers that she is related to the case and tracks down the real culprit through her. The real murderer had posted clues about his whereabouts online and invited relevant victims to the hotel on Christmas Eve, but the plan was discovered and blocked before it could be realized.
本书通过刑警、酒店服务人员和受害者的视角讲述了一起连环案件的终结，彰显出法制与道德的必要性。警方调查某连环案件后发现三个案子的死者均有案史，疑为遗属复仇。遗属都在同一天入住饭店，引起警方注意，开始卧底调查并力图避免第四案件发生。在饭店卧底时，刑警新田偶遇老同学、曾任法院检察官的三轮，发现对方与此案相关，并通过她追踪到真凶。真凶此时已在网上发出自己的行踪线索，邀请相关受害者在平安夜来到饭店，但在计划实现前被识破和阻拦。
本书通过刑警、酒店服务人员和受害者的视角讲述了一起连环案件的终结，彰显出法制与道德的必要性。警方调查某连环案件后发现三个案子的死者均有案史，疑为遗属复仇。遗属都在同一天入住饭店，引起警方注意，开始卧底调查并力图避免第四案件发生。在饭店卧底时，刑警新田偶遇老同学、曾任法院检察官的三轮，发现对方与此案相关，并通过她追踪到真凶。真凶此时已在网上发出自己的行踪线索，邀请相关受害者在平安夜来到饭店，但在计划实现前被识破和阻拦。
