Episode 13 of Heartbeat picks back up from the tussle inside the mansion. Woo-hyeol scares So-hi’s stalker away but then is lured in by In-hae’s blood. Do-sik rushes in and stops him. In a hospital room, Do-sik tucks in In-hae who says Woo-hyeol’s name in her sleep. Meanwhile, Woo-hyeol sits outside and vows to not hurt In-hae. Sang-hae, Dong-seop and Rose come to the house and find the place a mess.
In-hae wakes up in the hospital and Do-sik tells her she has a concussion. She asks about Woo-hyeol and Do-sik tells her what happened, although she can’t believe it. He tells her she should leave the mansion immediately.
While his friends are asleep, Woo-hyeol worries about not having heard from In-hae. He calls her but Do-sik picks up the phone while In-hae’s asleep. He refuses to tell Woo-hyeol anything and warns him to stay away. Do-sik even goes so far as to delete Woo-hyeol’s number from In-hae’s phone.
While thinking everything over, Woo-hyeol decides that if someone between the two of them has to die it will be him. A flashback shows the conversation between him and Yang-nam, where Woo-hyeol insists that he never wanted to become human at the cost of someone else’s life. At present, Yang-nam blames himself for the whole situation.
Dong-seop wakes up and Woo-hyeol brings him up to date. He asks Dong-seop what would have happened if he had woken up human. Dong-seop admits he’d be happy for Woo-hyeol but also sad that he won’t be immortal anymore. In the end, Woo-hyeol is glad In-hae woke him up early. Otherwise, he wouldn’t have met her.
In-hae still can’t believe that Woo-hyeol would ever hurt her and she gets ready to go home. Do-sik tells her Woo-hyeol plans on killing her just so he can turn human. In-hae says it’s not Woo-hyeol who needs her but she who needs Woo-hyeol.
Woo-hyeol gets a text from Hae-won, asking to meet her outside the house. He does and she returns the portrait of Hae-sun, admitting that it makes her sad. She asks what she can do to make Woo-hyeol look at her again. How can she be more like Hae-sun? Woo-hyeol says it’s his fault for looking for Hae-sun in Hae-won. He apologises to her for everything.
On her way home, In-hae maintains her belief in Woo-hyeol and tells herself she’ll help him become human. At the same time, Woo-hyeol realises he must leave In-hae to make sure she stays safe. In-hae sees Woo-hyeol standing on the road, runs over to him, and hugs him tight. She tells him to stay by her side. They return home and In-hae checks on Sang-hae and Dong-seop, making sure they’re doing their chores.
Woo-hyeol tells the two of them that he wants to speak to them later. So-hi approaches In-hae and apologises for everything. She thought she’d gotten rid of the stalker but he found her anyway. In-hae sympathises with her and So-hi thanks her for helping. Meanwhile, Hae-won calls her lawyer, clearly cooking up a plan.
Woo-hyeol and his friends discuss about In-hae’s father and how they can find him. They ask when Woo-hyeol plans to turn human, but he claims to want to find her father first. In-hae then texts him and calls him outside. She can tell that Woo-hyeol is upset about something. He says he feels bad about reacting to In-hae’s blood and doesn’t feel like he deserves to be in love. In-hae comforts him and tells him that he does deserve it.
Do-sik comes to his office to find Man-hwi lounging there. Do-sik agrees to pay him for the information and offers even more for Woo-hyeol’s blood. Now that Do-sik has seen the mark on Woo-hyeol’s neck, he’s sure that his blood will cure him of the curse.
Dong-seop gets fliers printed to find In-hae’s father. Woo-hyeol and Sang-hae hand them out while Dong-seop stays behind to make sure In-hae isn’t alone. However, nobody seems to know anything. They then come across Min-jae, Gwang-ok and Ki-suk. Woo-hyeol gives them the fliers and asks them to distribute them as well. Man-hwi watches everything from across the road.
Hae-won turns up at the mansion and hands In-hae a notice for investment withdrawal. She claims In-hae has deceived them by withholding the truth about Woo-hyeol. When In-hae says she doesn’t have the money, Hae-won tells her to hand over the mansion instead. In-hae puts her foot down and says she’ll pay all the money back but never give up on the mansion, or Woo-hyeol. Hae-won storms out of the house, giving her a week’s deadline.
Man-hwi goes to his secret hideout and looks at In-hae’s father, finally recognising who he is.
Woo-hyeol comes home and hears about Hae-won’s visit from Dong-seop. He goes up to see In-hae and asks her about it, but she lies and says it was nothing. Woo-hyeol, too, lies about where he was the whole day. He asks how In-hae would feel if her father was to turn up alive again. In-hae says she’s fine as long as she has Woo-hyeol.
Sang-hae and Dong-seop are discussing Woo-hyeol turning human when Yang-nam turns up all of a sudden. He reveals that Woo-hyeol is planning to leave them, for good. Woo-hyeol is looking at dark spots on his arm when his friends storm into the room and demand an explanation. They know everything. Woo-hyeol is happy to have lived a good life with good friends. They blame him for leaving them so abruptly, for the second time.
The next day after In-hae leaves the house, Woo-hyeol tries to talk to his friends but they’re still mad at him. In-hae goes to the bank but learns she probably won’t be approved for a loan. On her way back, Ki-suk tells her about the fliers for a missing person. Meanwhile, Woo-hyeol looks weaker than ever. He gets a call from someone who claims to have seen In-hae’s father. The call turns out to be from one of Man-hwi’s victims speaking on Man-hwi’s orders.
In-hae comes home and picks a fight with Sang-hae about the fliers they’ve distributed. She doesn’t understand why Woo-hyeol is doing this. She tries calling him but can’t get through. Meanwhile, Woo-hyeol gets to Man-hwi’s hideout and traces the smell of blood to the basement. He’s shocked to see cells filled with people as well as a cabinet stocked with bottles of blood.
But just as he turns around, a set of iron bars fall into place, trapping him inside. Man-hwi comes out of the shadows and gloats. When Woo-hyeol accuses him of hurting innocent people, Man-hwi claims they are nobodies. He then calls Do-sik with the good news. Woo-hyeol tries breaking out of the cell but he isn’t strong enough.
In another cell, In-hae’s father becomes alert after hearing Woo-hyeol’s name. Elsewhere, In-hae wonders why Woo-hyeol is looking for her father while Do-sik drives toward Man-hwi’s house.
With all its focus on flashbacks, this episode does become a bit slow. I understand the need to underline what Woo-hyeol and In-hae are thinking about but we don’t need to see entire scenes in the flashbacks. Shortening those would have definitely improved the episode and made it feel less like a drag.
That said, our main leads are really going through it and it shows. Both character’s emotions leap off the screen and that’s what keeps the story compelling. As a couple, they are easy to root for and Do-sik and Hae-won have now become antagonists that are highly fun to root against. Man-hwi, too, makes for a delightful villain. A particular shout out to Baek Seo-hoo for doing a wonderfully arrogant and despicable portrayal of Man-hwi.
Overall, this episode established a number of different obstacles for the lead pair to overcome. I wonder how long the two of them can keep lying to each other as well. Surrounded by multiple dangers, it will be interesting to see how the characters handle them.