In the enchanting opening of "Dynamite Kiss," we are introduced to Ko Da-rim, a young woman whose life has dealt her a cruel hand. As she drifts off to sleep on the bus, her dreams are as vivid as they are elusive—she dreams of being a CEO, with a dashing man proposing to her. The rhythm of her dreams nearly causes her to miss her stop, and with time pressing against her, she sprints all the way to school, even managing to lend a helping hand to a blind woman crossing the road.
For five long years, Da-rim has been tirelessly striving to pass her civil exam. She is the epitome of a model student, but the crux of her struggle lies in the interview phase. Despite her aspirations, she is prone to panicking in front of the panel. Her professor, while making light-hearted jests at her expense, provides her with a voucher for free monthly lectures—a sweet reprieve that she cherishes.
After school, Da-rim makes her way to the convenience store where she works with a diligence that reflects her determination. Later, she takes another bus home, her heart filled with anticipation as she shows her mother, Myeong-soon, and her sister, Da-jung, the dress she bought for the wedding. The twist? It's not Da-rim's wedding but rather Da-jung's. Unexpectedly, Da-jung reveals that she doesn't want Da-rim to attend, deeming her a blemish on her already precarious standing with her in-laws. To avoid the truth, she lied and said Da-rim works in the US and won't be able to make it.
Though hurt by this revelation, Da-rim manages to act excited about the trip to Jeju that Da-jung offers instead. In the solitude of her room, she overhears Myeong-soon scolding Da-jung for her selfishness. But Da-jung, with a heavy heart, laments that Da-rim didn't even get her a wedding gift.
Meanwhile, Kong Ji-hyuk finds himself in a meeting with investors from various countries, each with their own agenda and aspirations. The Arab investor's offer to buy the company in question adds another layer of intrigue to the already complex business negotiations.
With a determination that borders on obsession, he pledges to pay ten times the original sum, provided that Ji-hyuk engages the up-and-coming Korean developer, Kim Jeong-won. Upon successfully concluding the deal, Ji-hyuk's chum and business partner, Gyeong-min, proposes a night out to celebrate at a club. There, Gyeong-min tries to coax some female company into their orbit, but Ji-hyuk remains uninterested. He disdains love, believing it to be a foreign concept, while Gyeong-min believes it's merely a matter of time before Ji-hyuk meets his soulmate and changes his tune.
The next morning, a close female acquaintance pays a visit to Ji-hyuk's abode. Ha-young informs him that their parents have arranged for them to be matched for marriage. Stunned, Ji-hyuk bluntly rebuffs her proposal, even going so far as to mock her lipstick shade when she suggests a kiss.
Meanwhile, Da-rim pays a visit to her neighbor, Sun-woo's, for breakfast. Sun-woo, a single father, brings up the name Kim Jeong-won. It is then revealed that Jeong-won was Da-rim's ex. Da-rim warns him never to mention that name again, suggesting a lingering bitterness between them.
Sadly for Da-rim, it seems she cannot escape Jeong-won's shadow. At the airport, she spots a large poster advertising his upcoming lecture in Jeju. The sight of his face transports her back to the day they broke up. Jeong-won disparaged her for messing up in the interview and being unable to find a stable, well-paying job. He compared her to a limp piece of over-blanched spinach before abruptly ending things.
At the airport too is Ji-hyuk, on his way to present a business proposal to Jeong-won in Jeju. After arriving, he rents a car and asks Gyeong-min to conduct a background check on Jeong-won. He is banking on using Jeong-won's academic credentials to gain his favor, hoping to use his education as a lever in their dealings.
In the picturesque island of Jeju, Da-rim finds herself starving her way through life, saving every penny for a wedding gift to her beloved sister. Her excursions are marred by solitude, until an unexpected encounter with an old school friend, Su-jin, who is now dating Jeong-won, casts a shadow over their reunion. The two exes play a game of pretending not to recognize each other, but little does Da-rim know, Su-jin extends an invitation to lunch that she declines, plunging her into a deep depression.
Amidst her lethargy, her mother's call with news of the wedding gift purchase only serves to weigh her down further. Escaping to the beach, Da-rim finds solace in the memories of a failed interview that haunts her, the cruel words of interviewers echoing her family's and educational background. As she watches Ji-hyuk celebrate his victory near a cliff, she mistakes his exuberance for suicidal intent and impulsively reaches out to him. In her desperation to save him, she shares her life story, begging him to hold on. As he pushes her away, she stumbles backward, and in the chaos, he injures his hand while trying to save her. Da-rim collapses in a faint.
The scene shifts to the hospital, where Da-rim, still in a drunken slumber, speaks in her sleep, pleading with Ji-hyuk not to end his life due to his good looks. After his hand is treated, Ji-hyuk leaves Da-rim behind. Upon waking up, the hospital presents her with a bill for their medical expenses, forcing her to use the money she had hoarded for the gift on clearing the debt. With no money left, she trudges back to the hotel, her heart heavy.
The next morning, Gyeong-min calls Ji-hyuk, warning him about Jeong-won's aversion to discussing their high school days. They decide to focus on Jeong-won's college experience instead. Meanwhile, Da-rim spots Ji-hyuk having breakfast at the hotel and confronts him, demanding her money back. As they talk, Ji-hyuk spots Jeong-won and Su-jin. To cover her lie about being in Jeju with her boyfriend, Da-rim introduces Ji-hyuk as her lover. Fascinated by this newfound opportunity, Ji-hyuk plays along and accepts Su-jin's breakfast invite.
At breakfast, they present a convincing front as a couple in love. However, the awkward moments surface when Da-rim 'forgets' her boyfriend's name, creating a rift between them but also serving as a catalyst for Ji-hyuk's scheme to get closer to Jeong-won.
The conversation seamlessly shifted to matters of work, and Ji-hyuk seized this moment to formally introduce himself to Jeong-won in a professional manner. He extended an invitation to the couple for a party that evening. On their way back from the restaurant, Ji-hyuk and Da-rim were compelled to continue their charade in his hotel room.
Ji-hyuk proposed to pay Da-rim ten times the hospital bill in exchange for her acting as his girlfriend for the day in the hotel room. He added that it would be a delightful revenge against her ex. Da-rim hesitated but agreed after hearing the substantial amount she would receive.
Before the party, Ji-hyuk took Da-rim to a luxurious fashion store. She dragged him out, citing the expensive clothes. Ji-hyuk explained it was an investment and he wouldn't have her dressed shabbily. Da-rim was hurt by his words and demanded an apology.
As they bickered, a pregnant woman holding a child dropped her tangerines on the road. Da-rim offered to help her and got Ji-hyuk to cooperate. After witnessing her kindness, Ji-hyuk apologized and explained that he wanted Jeong-won to regret hurting Da-rim after she appeared dressed to the nines.
He took her back to the store and got a glam team. By the end of it, Da-rim was beyond stunning. Ji-hyuk took all the glory, calling himself her fairy godfather.
At the party, Jeong-won tried to catch Da-rim and Ji-hyuk in a lie. He was furious to hear that the couple was planning to get married in the coming spring. He grew even angrier as Ji-hyuk and Da-rim flawlessly dodged all his traps.
He cornered Da-rim and offered her money to reveal the truth about her relationship with Ji-hyuk. However, Da-rim effortlessly put him in his place, making him wonder even more if she was in love with Ji-hyuk. Simultaneously, Da-rim and Ji-hyuk successfully lured Jeong-won into wanting to learn more about his business.
As Jeong-won started asking more personal questions, Da-rim pretended to feel sick and pulled Ji-hyuk aside. As they talked, planning their next move, the other guests moved outside to see the fireworks display.
As Jeong-won got close, Da-rim tried to signal Ji-hyuk to stop talking but unfortunately, he didn't understand her signals. In the end, she kissed him, and he was startled as his heart started beating fast. As Jeong-won and Su-jin moved away, Da-rim pulled away and apologized. Ji-hyuk pulled her back and asked for another kiss. This time, he kissed her more deeply and passionately as the fireworks went off.
In the background, Ji-hyuk narrated about that first magical kiss, claiming it was a dynamite kiss.
