Due to an accident, Tae Poong only has the mental capability of a seven-year-old. Yu Jung, his next-door neighbor, has an upcoming audition to be a radio host. Tae Poong helps her practice before the big day. Meanwhile, Tae Poong’s mother does what her son asks without question.

Kyung Hee sends Tae Poong home with Dae Chul from the hospital. Yu Ra finds out that she wasn’t offered the DJ position she really wanted, and she confronts Na Young for taking it instead. Su Hee and Sang Hyeon see a hypnotist to bring back Su Hee’s memory.

Kyung Hye meets Ji Yeon through a marriage matchmaking service. She likes her right away and introduces her to Tae Poong. Meanwhile, Yu Ra takes a pregnancy test. When she discovers she’s pregnant, she decides to marry Jun Seok. They travel to Jun Seok’s hometown for the wedding, where his family awaits.

Tae Poong’s mother meets Ji Yeon at the welfare center and invites her to dinner. Ji Yeon seems like the best possible potential spouse for Tae Poong. Yu Jung spies on Ji Yeon in the restaurant while she’s at work and quickly discovers how horrible she is. Then, Yu Myung takes Tae Poong to a party and loses him.

Yu Jung finds Tae Poong alone as she planned and takes him to a motel to spend the night. She intentionally lets her mother find her pregnancy test. Yu Jung tells Mrs. Lee that she’s pregnant with Tae Poong’s baby, just as Yu Ra is on her way home to confess her love.

Yu Ra’s parents are devastated to find out that Tae Poong is the father of Yu Ra’s baby. Yu Jung senses something is uncanny about the situation. Kyung Hye decides to have Tae Poong and Yu Ra marry, despite sensing something unusual.

Yu Ra wants to marry Tae Poong before Jun Seok wakes up. Yu Jung keeps asking Yu Ra about what happened that day, and Yu Ra gets anxious that she might find out the truth. The wedding day plans were going well, up until Yu Jung collapses due to her cold.

Sook Ha scolds Yu Jung for ruining Yu Ra’s wedding. Tae Poong realizes he has feelings for her twin sister, Yu Jung, and refuses to marry Yu Ra. Yu Jung tells Tae Poong to keep his feelings for her a secret. Meanwhile, Yu Ra works on a scheme to get revenge on Na Young.

Yu Ra decides to register her marriage as soon as possible, and Kyung Hye wants to be there. As Yu Ra is about to submit the papers, someone sends her a text message telling her to stop. The messages tell her to go to a clinic with her mother-in-law, or else the photo with Jun Seok will be sent to Kyung Hye.

Jun Seok’s younger brother, Mr. Kim, tells Yu Ra to get a paternity test after she gives birth. She tries various methods to keep it a secret, but Mr. Kim is always one step ahead of her. Seo Jun is sent to a production plant in Chuncheon by his father, Chairman Cha.

Ji Seok insists on getting a paternity test on the baby immediately. Sang Hyeon thought he had given up on finding Su Hee's family until he gets a call from a woman claiming to have known Su Hee. Yu Ra starts to question Tae Poong's family's wealth.

Hwa Yeon realizes that Ji Sook is alive, so she orders Mr. Koo to never let her regain her memory. Yu Ra questions her mother-in-law's wealth and looks for proof of any assets by using Tae Poong. Sang Hyeon manages to find Mr. Koo's address and goes to his house.

Yu Ra continues to delay registering Min Woo's birth certificate since she finds out that Kyung Hye's company is in a difficult situation. Meanwhile, Hwa Yeon fabricates Su Hee's past to lose Sang Heon. Kyung Hye notices the materials were not made well at the construction site.

Sang Hyeon goes to see Woo Seok at his office and at home. Hwa Yeon tries to stop him from seeing her husband. Kyung Hye suddenly suggests that Yu Ra and Tae Poong go on a family trip. After getting back from the trip, Yu Ra finds Kyung Hye's final will.

Yu Ra finds out the foundation her mother-in-law has been donating to has been going through turmoil, so she tells her about it. She also pretends to care for Tae Poong in front of Kyung Hye in order to influence her last will. Sang Hyeon finally gets in touch with Woo Seok.

Yu Ra is worried about what Jun Seok will tell her mother-in-law. Sang Hyeon's family rushes into the hospital to see Sang Hyeon in critical condition. Kyung Hye has a lot on her mind, trying to deal with Yu Ra's ex-boyfriend while also digging into the irregularities made by the foundation at the same time.

Kyung Hye is arrested for a hit-and-run because there was a witness who testified against her. Sang Hyeon dies, and his family has a funeral for him. Tae Poong and Yu Jung try to get Kyung Hye out of jail by finding evidence that she wasn't at fault. They succeed in proving the witness's testimony is false.

Kyung Hye gets arrested again because of Yu Ra's testimony. Yu Ra tries to fabricate Kyung Hye's will and obtain ownership of Kyung Hye's properties. Meanwhile, Tae Poong shows a picture to Kyung Hye, and she finds out that it was Hwa Yeon who framed her.

Tae Poong struggles to accept the changes that occur now that Kyung Hye and Yu Ra are gone. Yu Ra leaves Min Woo and Tae Poong to start a new life. The guilt Hwa Yeon feels for the things she has done won't subside. Su Hee is still trying to get over her husband's death.

Tae Poong gets the dashcam footage from the lady next door and takes it to the detective. Unfortunately, Detective Choi has already been bribed by Hwa Yeon. Tae Poong is locked up in the rehabilitation center but manages to escape. When he's kidnapped again, he gets into a car accident.

Tae Poong wakes up with Savant syndrome and realizes he has higher intelligence than the average person. He changes his identity and leaves for the States with Su Hee. After he gets back to Korea, he becomes a prosecutor. Meanwhile, Yu Ra tries to get introduced to Seo Jun to pursue her ambition.

Yu Ra can't stop thinking that Min Hyuk is Tae Poong, so she tries to find out the truth herself. She invites him to her program once more and secretly obtains his fingerprints to compare them. Hwa Yeon tries to find a future spouse for Seo Jun.

Hwa Yeon is grateful to Yu Ra for saving her life, so she treats Yu Ra to a meal and likes what she sees. Tae Poong and Min Hyuk find the guy that gave false testimony and threaten him. Yu Jung hears a rumor that Tae Poong was seen somewhere.

Yu Jung finally encounters Tae Poong. Ever since Yu Ra saved Hwa Yeon's life, they've rapidly become closer friends. Su Hee has opened a store of her own, while Sook Ja has also purchased a new property to open her store.

Yu Jung's mother leaves a note saying she plans to kill herself and goes missing. Her family looks all over the town to find her. Min Hyuk finds out that Yu Ra is trying to marry Seo Jun. He finds a way to talk to Seo Jun. Yu Ra visits Min Hyuk's office, as she still doubts him.