MBC’s Friday-Saturday drama ″Married Woman Killer″ ranked first in its time slot, recording a 7.4% viewership rating nationwide (Nielsen Korea) from its first broadcast, with a peak rating of 9.4%. In the second episode, it surpassed 8.0% nationwide and peaked at 10.6%, securing the top spot among all Friday-Saturday dramas.

″Married Woman Killer″ depicts the struggles of a working mom striving to maintain work-life balance, revealing the double life of Yoo Bo-na (Gong Hyo-jin), an ordinary married woman who lives as the legendary sniper ″Kingfisher.″ In episode 1, a confrontation between father Oh Man-seok (Kim Won-hae), recently released from prison, and daughter Oh Seung-ah (Do Young-seo) on Christmas 15 years ago was shown. At the moment Oh Man-seok threatened his daughter, a bullet flew through a crack in the window and hit him, revealing Yoo Bo-na aiming her sniper rifle. Oh Seung-ah found a message saying ″Merry Christmas″ on the rooftop.

Back in the present, Yoo Bo-na lives an ordinary family life with her husband Kwon Tae-sung (Jung Joon-won) and daughter Kwon Yul (Hwang Bom-yi). However, she displays extraordinary traits, such as exceptional reflexes and subduing a sexual harasser. After returning from a three-year parental leave, Yoo Bo-na resumed her position as head of Sales Team 3 at Durumi Electronics. When team leader Kim Bong-pal (Sung Dong-il) asked her to work during the day, she replied, ″Let’s do it during the day. I have to pick up my child,″ surprising the team members. After returning to work, she was also shown assembling mysterious equipment on the church rooftop and swiftly neutralizing a target with her sniper rifle.

Meanwhile, Kwon Tae-sung received a tip about a new type of drug and headed to Musan. While chasing a man suspected to be a dropper, a car explosion occurred, and a mysterious man watching the scene appeared. At the Musan police station, Kwon Tae-sung investigated the case and discovered that the victim was a drug kingpin.

Lee Dong-jin (Lee Sang-yi) and Beom Seong-hoon (Choi Woo-sung) conducted a forensic investigation at the Kingfisher sniper scene. The victim, Hwang Min-ho (Son Seung-taek), had disguised his crime as an accident, killing his pregnant wife to collect insurance money but was only convicted of drunk driving murder and released after three years. Lee Dong-jin continued the investigation on the church rooftop, saying, ″Nice to see you, Kingfisher.″ Scenes alternated with Yoo Bo-na undergoing intense training in an underground facility and equipping her sniper rifle, setting up a confrontation.

Kwon Tae-sung suspected the Musan car explosion was a homicide. It was revealed that Kwon Tae-sung had nearly died at the Kingfisher sniper scene in the past, and breaking news announced Kingfisher’s return. Yoo Bo-na sang a lullaby during a video call with her daughter Kwon Yul, and the members of Durumi Electronics Sales Team 3 watching said in surprise, ″Kingfisher has become a mom.″

Lee Dong-jin informed Kwon Tae-sung about a baby shark sticker found at the sniper location. Kwon Tae-sung said, ″She might have gotten married, started a family, and had a child. Like me,″ showing tension as he looked at the baby shark sticker on Yoo Bo-na’s clothes. Yoo Bo-na received a warning letter containing family photos and images of the sniper scene from a mysterious person.

A new employee specializing in poisoning, Oh Hyun-nam, appeared in Durumi Electronics Sales Team 3. Kim Bong-pal installed an LPG gas tank in a vehicle, and Bong Tae-min (Kim Nam-hee) opened the gas valve to induce an explosion, revealing the hidden identities of the team members and the truth behind the Musan car explosion. Oh Hyun-nam gave Yoo Bo-na a meaningful greeting and asked at a team dinner, ″How would you feel if you lost something precious?″

At the end of the broadcast, Kwon Tae-sung received a tip about Kingfisher and headed to a café, where Yoo Bo-na received a threatening message containing a photo of a sleeping Kwon Tae-sung. The mastermind was Oh Hyun-nam, whose real name was Oh Seung-ah. It was revealed that she was a witness to the sniper incident involving her father Oh Man-seok 15 years ago. Yoo Bo-na confronted Oh Hyun-nam, aiming her sniper rifle, and Oh Hyun-nam threatened that she had given Kwon Tae-sung ″MistS.″ The episode ended with Yoo Bo-na drinking poison, saying, ″Do you want to kill my husband? Then kill me too.″