Episode 18 recap: The secrets of the butterfly fairy are gradually surfacing.

The groom's death has been confirmed. Jin Ling examines his body and finds a footprint at the crime scene. In the groom's mouth, Jin Ling discovers a butterfly cocoon. The groom's mother cries with the maid, saying the butterfly has come back to take revenge, but the groom's father tells her not to talk nonsense. Jin Ling estimates the time of death to be within 4-8 hours.

After discussing with Jin Ling and Tan Jing Tian, the detective decides to first talk to the maid to understand more about her talk of retribution. Meanwhile, De has already sent people to search for the detective. Tan Jing Tian thinks of the auntie who fed them that day, as she seemed friendly, so they decide to ask her first. The detective shows the auntie his police badge, and she then reveals the truth.

Hu Die was a bride bought by the elder son of the maid. This scarred girl in the wheelchair is her, though they don't know her true identity yet. The maid introduced her to the family members, including her daughter Songxi, in addition to the two sons.

However, the maid's two sons have mental issues. Hu Die was constantly trying to escape after being abducted. Later, the maid's husband raped Hu Die. After Hu Die married the elder son, she stopped causing trouble and seemed to have also become mentally unsound, just accompanying the son's mischief.

One time the elder son fell and died, but the investigation found nothing unusual about his death. The maid thought she spent a lot to buy Hu Die, so she decided to have Hu Die marry the younger son. But then a mysterious fire broke out, killing Hu Die and badly burning Songxi's face beyond recognition.

Many people in this village were kidnapped and sold, including the auntie herself and the maid. After having children, they just resigned themselves to their fate. Based on the auntie's description, Tan Jing Tian finds it suspicious. Ever since Hu Die's death, this family has been cursed, with constant incidents and the sound of a woman's cries.

The auntie takes them to the burned house, the same one where the maid saw butterflies dripping blood from the roof. However, the elder advises them not to reveal they are police, as previously police who came to rescue kidnapped women were chased away by the villagers.

Tan Jing Tian has a plan. He has a drop of red "butterfly blood" in a bottle, and explains to the maid that this is just normal butterfly excrement, not anything supernatural. The intention is to make the maid open up about Hu Die's story.

The maid tells them that she previously encountered a spiritual master who accurately described Hu Die's death by fire. The master instructed her to arrange Hu Die's Buddhist statues, and later have her second son marry a speechless orphan girl. The maid followed the master's guidance.

Based on the maid's recounting, the detective deduces the next victim will be the new bride. They find the bride locked in the warehouse by the maid's husband, who tries to stop them from rescuing her. In the end, they discover the bride has already hanged herself.

Meanwhile, De has tracked down the detective's vehicle and orders his men to search and shoot on sight.