LTNS - Season 1

Woo-jin and Samuel used to be deeply in love and very passionate about each other. However, after being married for a long time, the days of burning with sexual desire are long gone, and they become a sexless couple. One day, Samuel finds out his friend, Jung-soo, is having an affair. Woo-jin insists on telling Se-yeon about the truth.

As life hits them hard, Samuel and Woo-jin decide to work together and blacklist the couples who are cheating on their partners for money. Woo-jin finds targets from the hotel she is working at, and Samuel puts a tail on them. Meanwhile, despite their financial difficulty, they spend the money they made on Samuel's father's birthday and Woo-jin's niece's academy fee.

Samuel and Woo Jin look for another target. An old man comes to Woo Jin's hotel, and it seems like he's having an affair. Samuel and Woo Jin follow the couple to the mountains and the sea to gather evidence that they can use to blackmail the couple. However, the old man suggests they meet up at his company if the two want to get money from him.

Samuel and Woo Jin are having a hard time finding a new target. One night, a couple gets into Samuel's taxi, and it seems like they are having an affair. Samuel and Woo Jin try to make an effort for their relationship as they see the passionate adultery couple. They thought they successfully ripped off the money, but Samuel gets into an accident while running away.

Woo-jin goes to the hospital and Samuel is not in the bed. It turns out that Samuel is with Min-soo, his neighbor and also cleaning mate in the past. Woo-jin calls him and catches him lying. She decides to tail him to see what is going on.

Woo-jin thinks about her relationship with Samuel and tries to figure out when and where everything started to go wrong. Feeling betrayed, she decides to blackmail the woman next door. Woo-jin questions Samuel, and Samuel tells her a secret he has been keeping. Woo-jin is flustered, and it becomes a huge fight. What will be the end of this couple?