The story depicts how a couple who began with love drift toward suspicion and conflict. On Channel A's 'The Detectives' Trade Secrets,' airing September 21 at 10 p.m., a case will be revealed in which an older sister who suspects her younger brother of infidelity hires the detective team.

Women's Underwear and Hotel Card Key Found in Brother's Bag

The client's younger brother married a wife he met at a Bible study group, and the couple overcame hardships together. With popular lectures and financial stability, he was living a successful life with his family. However, when his sister visited his home after a long time, she sensed a cold atmosphere between the couple and discovered women's underwear and a hotel card key in her brother's bag. In addition, an acquaintance reported witnessing the brother entering a hotel with a woman, further fueling the affair allegations.

The detective team's pursuit captured a decisive scene. The brother was seen being affectionate with a woman at a hotel bar and even entering a hotel room together, all caught on camera.

Sister-in-Law Visits Fortune Teller... 'This Time I'll Finish Him Off Properly'

Along with this, footage will also be released showing the brother's wife visiting a fortune teller and talking with a shaman. The shaman warned, 'If you can't kill that person, you'll die!' and the wife said, 'This time I'll finish him off properly,' deepening suspicions. The client also expressed doubt, saying, 'It seems my sister-in-law, having tasted money, is trying to harm my brother and take his assets.'

Director Bong Man-dae Joins as One-Day Detective... 'Married 22 Years, It Feels Like Being Denied a Loan'

Director Bong Man-dae appears on the broadcast as a one-day detective, sharing his own marital experiences. After recalling his past remark, 'To reconcile with a loved one, use letters when dating, money when married, and physical affection later on,' he opened up about the reality of being married for 22 years. 'My wife pushes away even simple touches and communication. She always lives with earphones in,' he said, adding, 'It feels like going to a bank and being denied a loan.'

Cases of overcoming marital rut were also introduced, such as a couple who 'go to the mountains with a tent every winter, and even go backpacking when snowstorms rage and mountain access is restricted.'

Kim Poong Says 'They Seem Possessed by Demons'... Panel Reactions Draw Attention

The panelists' reactions are also drawing attention. Kim Poong said of the couple's story, 'They seem possessed by demons,' Yoo In-na said, 'It's too horrific,' and Defconn said, 'It's terrifying.' After hearing Director Bong Man-dae's method for overcoming marital rut, Defconn added, 'Once this airs, hiking trails will be packed this winter.'

All of these stories can be seen on Channel A's 'The Detectives' Trade Secrets' on September 21 at 10 p.m.