Anthrophobe, Cha Hong Do (Choi Gang Hee) tails a firetruck with wailing sirens. She manages to drive her scooter ahead of the firetruck just as they arrive at the office of psychiatrist, Ko Yi Seok (Chun Jung Myung). There is white smoke billowing out of the windows, but the firetruck races past. A desperate Hong Do rushes into the building screaming for Yi Seok, but finds no one.
We backtrack to the moments before police detective, Jang Doo Soo (Lee Jae Yoon) came across Yi Seok lying on top of Hong Do. Hong Do and Yi Seok flirt then rough house. Doo Soo looks crestfallen and walks away.
Hong Do grabs her helmet and catches up to Doo Soo. He expresses relief that she is safe and appears to be making progress in her treatment. Hong Do fails to say a single word as a downcast Doo Soo leaves.
Back in the office, Yi Seok reads Hong Do’s journal, which reveals nothing. A frustrated Yi Seok criticizes Doo Soo for wanting what he can’t have, then lets slip that Hong Do’s crush knows that she slept with Yi Seok. Yi Seok is suddenly beset by cockroaches then comes under attack from an enraged Hong Do.
After working out his frustration over Hong Do and Yi Seok with judo, Doo Soo finds Hong Do waiting for him outside his apartment. Hong Do can only apologize, but Doo Soo points out that she has nothing to feel guilty about.
Yi Seok is also working out his issues on a stationary bike. He thinks back to the moment when he uncharacteristically returned to bed with Hong Do then spent the rest of the night with her.
The next day, Doo Soo spots Hong Do dressed up as old lady, Oh Young Rae at the bus stop. A bus pulls up between them, but while Hong Do chooses to miss her bus for a chance to see Doo Soo again, he has already driven away. Young Rae receives a friendlier reception from the Chairman (Joo Hyun) who seems open to her suggestions about his book.
Doo Soo is called out to a café by his fiancée who is reconsidering their marriage. She correctly surmises that Doo Soo does not love her.
Yi Seok’s guilt over upsetting Hong Do compels him to repeat his request for Hong Do’s home address from Doo Soo. Hilariously, Yi Seok claims that he deserves the information, because it was difficult for him to make the request of Doo Soo. Again, Doo Soo refuses to divulge.
As Yi Seok leaves, pettily claiming to be headed to a private investigator for Hong Do’s address, Doo Soo tells him to stay away from her. Yi Seok pointedly asks Doo Soo when he is getting married. Doo Soo wrist grabs Yi Seok, and the boys quarrel over Hong Do. Afterwards, a frustrated Doo Soo has a fit with the vending machine, and reveals to his partner that he won’t be getting married.
Hong Do is drinking soju while cleaning her floor when she rejects a call from Yi Seok. She does listen to his voice message in which he chides her for repeatedly breaking off contact. He shamelessly reports that he asked Doo Soo for her address. Oblivious Yi Seok does have a point when he tells Hong Do that she cannot just hide from her problems, but should face them head on.
Hong Do takes Yi Seok up on his challenge, and marches into Yi Seok’s office, looking for a fight. She launches into a tirade over his repeat harassment of Doo Soo. Yi Seok offers to stop bothering Doo Soo in exchange for her home address. When Hong Do expresses regret over sleeping with Yi Seok, he appears sincere in his apology, admitting that he was thoughtless. However, Hong Do cannot bring herself to trust him.
The next morning, Hong Do’s desk is empty, but Yi Seok finds an obnoxious school girl at his desk, seeking counselling. His tinnitus starts up, but the ill-mannered student refuses to leave. Yi Seok goes to his mentor, Uhm Gi Choon (Seo Yi Sook) to complain, and learns that the student is her wealthy friend’s daughter. Yi Seok makes cracks about Gi Choon’s single status, and ducks a flying tissue box.
Yi Seok returns to his office, and represses a smile upon finding Hong Do back at her desk. He tries to kick out the student who seems intent on being uncooperative, but Hong Do directs him to treat her, any way.
Yi Seok’s sister, Ko Se Ro (Ahn So Hee) is doing yoga at home when Yi Seok confronts her about being carried home drunk by a policeman, unaware that it was Doo Soo. Se Ro claims to be doing research for her acting.
The Chairman and Young Rae (aka Hong Do) are bonding over a 68-year-old bicycle as his disapproving housekeeper monitors them. The Chairman reveals that his grandson, Yi Seok stubbornly sticks to a task no matter how difficult, which gives Hong Do pause.
Gi Choon is cursing out Yi Seok over the phone for taking his mother out for a drive when Gi Choon came out to the Chairman’s home to treat her. Plus, his mother has not taken her medication. The butler suddenly steps up, and unnerves Gi Choon by offering her coffee then scratching his ass.
Yi Seok’s outing with his mother is interrupted by a call from his father. His mother insists on rushing home to go meet up with her husband. Young Rae has just taken her leave of the Chairman, and witnesses Yi Seok warning his father that his mother is not in good mental shape. Yi Seok’s father just taunts his son and dismisses his professional opinion.
Driving away from the Chairman’s house, Yi Seok comes across Young Rae, and offers to give her a ride home. Fearful of being found out, Young Rae attempts to escape, but Yi Seok manages to catch up to her as she is slipping and falling on the ice. Yi Seok is highly amused as the old woman throws off his helping hands, and climbs into the back seat like a boss. In the car, Young Rae is pleasantly surprised by this patient and affable side of Yi Seok.
Yi Seok has just dropped Young Rae off when he receives a call from Se Ro about their mother. He rushes back to the Chairman’s home where his mother is crying after having an episode, his sister is exasperated, and his father is nowhere to be found.
Hong Do is at home, troubled by what might have befallen Yi Seok’s mother. She calls Yi Seok out of concern, and he asks to meet up with her. In person, Hong Do mirrors her old woman persona when she rejects Yi Seok’s front seat in favour of sitting alone in the back seat of his car.
Hong Do decides to have a session on the spot, and tells Yi Seok about being abandoned by both of her parents, and raised by her grandmother. She started becoming housebound as a teenager when the bullying became too much, and was incapable of leaving the house even when her grandmother was taken to the hospital.
Yi Seok comforts a guilt ridden Hong Do then randomly proposes that they date. He has a scientific curiosity about their connection. Put off by his casual attitude towards relationships, Hong Do stuns Yi Seok by rejecting him outright.
Yi Seok and Hong Do continue to be at odds in the office. However, they instantly unite during a meeting with the ill-mannered student and her icy mother.
In the aftermath of his grandfather’s sudden death, Doo Soo abruptly decides to run to Hong Do’s home in his funeral suit. The cloud visibly lifts from Doo Soo as he decides, belatedly, to pursue Hong Do.
Hong Do wakes up to a message from Doo Soo asking to meet with her. She is a whirlwind of activity as she rushes out the door. Hong Do has just started up her scooter when she receives a call from Yi Seok. He is coughing, mentions a fire, and asks her to hurry to the office.
Hong Do initially dismisses Yi Seok, but the sight of a firetruck racing past convinces her that he was telling the truth. Doo Soo is anxiously waiting to declare his intentions to Hong Do when he spots both the firetruck and Hong Do speeding past.
We are back to the future with Hong Do running into the smoky office, calling for Yi Seok. Not finding him, she runs back out where Yi Seok is standing by his car, chuckling. It turns out that the smoke was intended to kill two birds with one stone: one being the cockroach problem, and the other being Yi Seok’s doubts that Hong Do cares about him. Yi Seok offers to treat her to a meal as compensation for her distress. Hong Do decides, instead, to wring his neck.
This was generally a more stressful episode than the last. Both Hong Do and Doo Soo were raging over the loss of a relationship with one another. The instigator of the trouble, Yi Seok was amazingly myopic and selfish; it was amusing, but only from a distance as a spectator. What saves Yi Seok as a sympathetic character is that he manages to feel guilty about his careless ways, and we discover that he pales in comparison to his father.
The love triangle is pretty strong. Choi Kang Hee and Chun Jung Myung have demonstrated great chemistry, but the animosity between the male leads has become intense. Now that Doo Soo has decided to play, we are assured of much entertainment in the weeks to come.
A final thought: when was the last time a Kdrama female lead admitted to watching porn by herself? It is just one of the many things that make “Heart to Heart” awesome.