Episode 4 picks up with Yeong-won finding out that Sa-gang knew about Jae-jin’s affair and Sa gang barely prevents her from reporting it to the police.
At her TV show afterwards, Yeong-won encounters a case study resembling her own situation and counsels the woman to endure the struggle, recommending that she seek legal reparation. Upon exiting the studio, Yeong-won is given a toy car by an unknown sender. She attempts to determine the sender without success. Upon returning to her office, she discovers a message written in invisible ink under the toy car. She finds a video of the toy car crashing into an aquarium after clicking on the URL. The fact that the toy car bears Jae-jin’s car number indicates that Jae-jin is the next target.
Sa-gang and Yeong-won go to the police station and discover that Seung-jae, Kang-sung’s nephew, was responsible for the spy camera. Kang-sung requested Seung-jae to plant the camera. As a result, Sa-gang forgives him, and they drop the charges.
Once Sa-gang departs, Yeong-won asks Kyung-tae to come to her clinic for counseling in order to help locate Jae-jin. After seeing Jae-jin’s pictures on Dr. Oh’s phone, Kyung-tae is ready to assist in locating her, worried about their worsening relationship. In the meantime, Sa-gang also suggests that Kang-sung should contact Kyung-tae to inquire about Dr. Oh’s sudden absence.
Kyung-tae, along with Kang-sung, is actively following Jae-jin’s car. At home, Yeong-won discovers Tae-oh, who has arrived to teach Do-hyun, and later suggests to her son that they should plan a trip together in the near future.
The next day, Kyung-tae shows Yeong-won surveillance video of Jae-jin’s trip. The video indicates that Se-na was with Jae-jin, not Dr. Oh. Yeong-won sets off on a trip to the final known whereabouts of Jae-jin. In a different location, Sa-gang discovers the same place and meets up with Yeong-won during her travels. They both continue on their journey to find Jae-jin together.
Upon arrival at the site, they discover that Jae-jin has embarked on a ferry headed to an island. Sa-gang and Yeong-won go to the island with Kang-sung and Yeong-min. They participate in a video call with Dr. Oh, who has just woke up and is shouting anxiously, “We were on the brink of destruction.” My Jae-jin will always be alive!
While on the ferry, Sa-gang admits to knowing about Jae-jin’s affair from the beginning. She closely watched the two and wanted them to end their relationship when she offered Se-na money to break up with Jae-jin.
On the island, they head towards a restaurant that Jae-jin could have visited. The owner confirms the presence of Jae-jin and Se-na. A young delivery boy enters and informs them about a car found in the sea after a crash. Yeong-won and her companions swiftly make their way to the site and are shocked to find out that the vehicle is actually Jae-jin’s rented car, a heavy object suddenly falls from the car.
