Sidong attended the funeral of his deceased friend, Chen Fangxing. At the funeral, Nianxia, who sat next to Sidong, sent a message to Fangxing and received a 'bluetick'. Presuming it to be a childish prank, Sidong wasn't quite adamant about the 'bluetick' investigation. He is simply treating it as an excuse to get to know Nianxia. As he and Nianxia began their investigation, attendees of the funeral were murdered. Sidong started delving into the investigation. .. 莫思冬出席自小好友陈方行的葬礼，身旁的毕念夏发了个简讯给陈方行，竟然见「已读不回」的双蓝剔！思冬被念夏吸引，借追查为名，约会念夏。 本以为「已读不回」只是某个拿着陈方行遗物的人的恶作剧，思冬并没有用心去查，只是不断找借口约会念夏，开始约见其他葬礼出席者。追查期间，他们追查的出席者被杀。思冬终于觉得事情不简单，决定找出真相。
