As his pacemaker, Sang Ha is there to help Jin Won succeed in his marathon races.

Mr. Heart is a Korean BL drama about a university athlete who competes in marathons. This upbeat love story begins when he's introduced to a cute guy who motivates him to do better. You can pretty much guess what happens next. Actually, this series does take a sudden dramatic turn in its second half, but it still maintains a fairly lighthearted tone.

Mr. Heart doesn't exactly break new ground, relying on many generic narrative tropes. Nonetheless, it's a pleasant BL series with enough delightful moments to satisfy your appetite. The story is packed with energy, enthusiasm, and positivity.

Mr. Heart Summary


미스터 하트

Series Info:

South Korea (2020)


1 hour and 30 minutes

Total Episodes:

8 episodes


School romance


Mr. Heart is a happy & funny BL drama.


Jin Won and Sang Ha's personalities couldn't be more different, but opposites do attract...

Jin Won is a promising university athlete who used to win marathon races in high school, but he has fallen into a performance slump recently. His coach introduces him to Sang Ha, an enthusiastic freshman who takes on the role of Jin Won's pacemaker. A pacemaker's job is to help the runner maintain a steady pace at the start of competitions. Although Jin Won is prideful and doesn't see the value in a pacemaker, Sang Ha proves his worth and joins the training routine.

Secretly, Sang Ha has harboured a lengthy crush on Jin Won since their days in high school. However, he hadn't confessed his feelings and his small thoughtful gestures were never given credit. Now, imagine Sang Ha's shock when he woke up one morning in his dorm room, with a half-naked Jin Won wrapped around him in bed. It had been a complete accident, caused by Jin Won simply walking into the wrong room during the night.

While this incident left Jin Won embarrassed and flustered, it encouraged Sang Ha to work up the courage and finally confess his feelings. This confession comes as a total shock to Jin Wong, who doesn't quite know how to navigate the tricky relationship dynamic with his training mate.

Mr. Heart Cast


Jin Won Chun Seung Ho (천승호) Chun Sung Ho Instagram

Jin Won is played by the actor Jin Won Chun Seung Ho (천승호).

Jin Won is a talented university athlete who competes in marathons, aspiring to compete in national races. He used to come in first place in high school races. But now? Not so much. With his confidence shaken, Jin Won wonders if he'll ever find his stride again.

Sang Ha Lee Se Jin (이세진) Lee Se Jin Instagram

Sang Ha is played by the actor Lee Se Jin (이세진).

Sang Ha is a bubbly and enthusiastic pacemaker who wants to help Jin Won succeed in his races. He worked as a milk delivery boy since high school, always saving any leftover boxes of milk for Jin Won. He practically stalked Jin Won from high school all the way to university.

Supporting Cast

Hyo Ri is played by the actress Lara (라라).

Hyo Ri

Lara (라라)

Coach Bong is played by the actor Yoo Jang Young (유장영).

Coach Bong

Yoo Jang Young (유장영)

Cast highlights

  • The leads (Chung Seung Ho and Lee Se Jin) have a guest appearance in the 2023 series Jun and Jun.
  • Sang Ha's actor (Lee Se Jin) is one of the leads in the 2021 Korean BL drama, Nobleman Ryu's Wedding. He takes on a ~very~ different identity in this series.

Mr. Heart Review


Drama Review Score: 6.6

Jin Wong and Sang Ha get close as they train for the marathon together.

Mr. Heart is missing a few key components of any successful BL drama: a likable lead, an endearing romance, and an interesting story. Now, these might sound like incredibly critical flaws, but they aren't as noticeable when you're watching each 11-minute episode in small doses. For most of the series, Mr. Heart maintains its lighthearted charm and upbeat energy. This show is an enjoyable experience, even if it feels lacklustre in some areas.

Despite some poor storytelling choices, my overall opinion of Mr. Heart is a positive one. I guess my expectations weren't that high, but I'm always keen on watching a short, simple, and sweet BL drama with a happy ending.

Even though Mr. Heart has room for improvement, fans of the genre should still be able to enjoy some of the cute, fluffy moments in this BL series. Plus, you'll get to experience Sang Ha's character, who is totally adorable and worth watching just for him.


OK story

Jin Won seems fascinated by Sang Ha's nipples at times.

Admittedly, a story about a marathon runner doesn't sound like the most interesting plot on paper, or at least not the way Mr. Heart portrayed it. Jin Won's journey goes smoothly without any kind of dramatic tension: some minimal training, some light running, and then he just wins the races. Couldn't they have thrown in an injury or a rival to spruce things up a little?

Mr. Heart started out as a lighthearted series, but takes a strange dramatic turn later on. Sang Ha's loan shark storyline hijacked the second half of the series, even overshadowing the big marathon in the end. This was a weirdly sinister plot that clashed with the pleasant and upbeat vibe of the series. The story didn't make a lot of sense and all the ridiculous scenes were just dumb to watch. I signed up to watch a BL series about running in marathons, not running away from loan sharks!

I actually think Sang Ha's financial struggles could be an interesting angle for the story, but they needed to take down the intensity by a couple notches. Maybe focus on Sang Ha struggling to pay his university tuition or something less serious. Give us a more realistic and relatable storyline than getting chased down by loan sharks.


Jin Won and Sang Ha

Jin Won and Sang Ha in a fantasy sequence.

As a couple, Jin Won and Sang Ha do share a couple of cute moments together. Many of these scenes are silly and don't really add much to the plot, but I quite like them. This type of fluff is Mr. Heart's strong suit. It's sweet, it's lighthearted, and it's great content to appeal to a BL fan like me. 😊

As cute as these scenes were, the romance between Jin Won and Sang Ha never clicked. It didn't seem like their feelings were reciprocated. There were even times when Jin Won gave the impression that he didn't like Sang Ha very much. He's always saying mean things to him or making some kind of fuss when they're together. His demeanour doesn't resemble a guy who’s falling in love.

It took too long for Jin Won to warm to Sang Ha, and their feelings weren’t seemingly on the same level. As Sang Ha said himself, he was an underdog in their relationship because he liked Jin Won so much more. If Jin Won had acted nicer and more receptive towards Sang Ha early on, I’d be more on board with their romance.


Decent acting

It took a while for Jin Wong and Sang Ha to get together.

Since Jin Won’s character is so one-dimensional, the role doesn’t give his actor much to work with and he didn’t make a big impression. On the other hand, Sang Ha steals every scene with his natural charisma. He’s great at conveying his emotions on his expressive face. This kid can tell an entire story just by shifting his eyes on a certain way.

Best Character

Sang Ha

Sang Ha is a super charismatic character.

Sang Ha is delightful to watch. He just cracks me up with his exaggerated expressions and childlike demeanour. The actor (Lee Se Jin) has charisma in spades. He is super likable with enough charisma to carry the entire series by himself.

Energetic and easily excitable, his character brings a lot of much needed levity to this BL drama. Sang Ha has a natural charm that translates exceptionally well on screen. His adorable personality, his goofy mannerisms, and his overly exaggerated facial expressions never fail to make me laugh. He is maximum cuteness personified. 😊

Halfway through the series, I realized that I care about Sang Ha way more than I do about Jin Won. In a typical BL drama, you don't have to take sides because you like both of the guys equally. But here, I was on Team Sang Ha and rooting for him to find someone better than Jin Won.

Skin & Nudity

Shirtless scenes

Jin Wong and Sang Ha had shirtless scenes at the beginning.

No nudity, but there are a few shirtless scenes and Jin Won seems particularly fascinated with Sang Ha’s nipples. 🔎 We also see a lot of thighs and legs because of their short shorts. 🦵


Verbal abuse

Sang Ha reacts in shock after kissing Jin Won for the first time.

Sang Ha gets involved with a dangerous loan shark, who rough handles him in a few scenes. Jin Won can also be a bit verbally abusive towards Sang Ha.


The bath scene

Jin Won and Sang Ha take a bath together.

I really liked the scene where Jin Won and Sang Ha were taking a bath together, where they're just talking among themselves. There's one particularly memorable line that had me laugh out loud: "Don't talk. The mood gets either sad or erotic whenever you talk." This is such a great one-liner and I totally wanna steal this line to use in random contexts in the future.


Jin Won

Jin Won wasn't a very likable lead character.

This series went overboard in making Jin Won too standoffish as a character. Jin Won needed to show more sensitivity and vulnerability earlier, instead of waiting until the last few moments to act like a sweet and tender boyfriend.

Jin Won was the most likable in the first episode, back when we don't know anything about his personality. Once we get to know him better, his character is rude, prickly, and consistently mean to Sang Ha. Every time he starts to mellow, it's followed by another scene of him acting like a jerk to Sang Ha again. It's always two steps forward and one step back back with this guy.

At one point, even his friend had to intervene, telling him to be nicer and show more empathy towards Sang Ha. I'm sorry, but Jin Wong shouldn't need a reminder to behave like a good person. 😑 When the lead is too unlikable, I don't get invested in his story, his successes, or his relationships. Who cares if Jin Won wins or loses the marathon? Screw him.


OK ending

Jin Won and Sang Ha kiss in the end.

There should've been a lot of drama when Sang Ha won the marathon and claimed the prize money for himself. This was supposed to be a huge betrayal, since Jin Won was working so hard towards his goal, and then Sang Ha came swooping in to steal the victory from him.

Unfortunately, nothing happened. Although Sang Ha is seen moping around for a few minutes, we don't explore the consequences of his actions. He was just forgiven afterwards and even got kissed by Jin Won as a reward. Everything just got resolved neatly, which is kind of lame. If there was going to be no conflict whatsoever, then why even bother with this unnecessary twist?

I wished Jin Won and Sang Ha actually had a lengthy and mature conversation about what happened in the race. In the original ending, I liked the part where Jin Won said he wanted to see Sang Ha as an equal in their relationship. The sentiment was good, but it needed more build-up. With better storytelling, this could've been a great opportunity to explore their emotions with more complexity.

Mr. Heart Information


W-STORY is the Korean BL studio that made Where Your Eyes Linger (2020).

W-STORY is the Korean BL studio that made Where Your Eyes Linger (2020). Its portfolio also includes Mr. Heart (2020), You Make Me Dance (2021), Cherry Blossoms After Winter (2022), and Jun and Jun (2023).

  1. Was it a red flag for anyone else when Jin Woo punched Sang Ha (who weighs 80 pounds soaking wet) hard in the face and then they decide to start dating? Even before that Jin Woo never saw past his own convenience and privilege to understand what Sang Ha was going through. I have real concerns for the mochi who just got out from under his loan shark only to end up with this guy.

Leave a Reply

Your email address will not be published. Required fields are marked *

BL Watcher - Best BL Dramas, Movies & Anime Reviews