After the death-row inmate Jang Joo-jin painfully gave birth to her daughter Soo-min, she was tormented by immense inner pain. Her husband had abandoned her, and she wouldn't live much longer, which meant her daughter would inevitably have to live a lonely life in this world! Coincidentally at this time, another mother in the same room, Oh Chung-yeon, also gave birth to a daughter. Oh Chung-yeon's husband, Wang Hyeok-yu, owned a very influential listed company, and their family was extremely wealthy. To change the fate of her daughter, which was destined to be tragic, after much hesitation, Jang Joo-jin finally made an immoral decision to switch the two children when no one was paying attention. Thus, the daughter of the death-row inmate, Soo-min, moved into a mansion and lived a life of luxury like a princess; while the rightful rich girl, Bae-reum, was taken to the countryside and entrusted to Jang Joo-jin's former lover, Seo Baek-gun. She often suffered abuse from Seo Baek-gun's wife, Yang Jin-hwa, and bullying from her good-for-nothing son, Seo Jeong-bong. However, she couldn't bear seeing the kind Uncle Baek-gun quarrel with Auntie for her sake, so she silently endured her unfortunate childhood... But could Jang Joo-jin's evil act filled with love really bring lifelong happiness to her daughter Soo-min? Could the adopted Bae-reum never find her own path to happiness? Would their real identities be rewritten forever?
One day ten years later, Bae-reum followed Yang Jin-hwa to a villa to work, where she unintentionally met Wang Hyeok-yu's family who were on vacation there. Perhaps it was heaven's mercy? Or perhaps it was the innate familial bond? The beautiful and intelligent little Bae-reum deeply impressed Oh Chung-yeon, and was insisted to stay to accompany Soo-min, even being recognized as a goddaughter by the Wang family. The spoiled little Soo-min felt that her princess status was threatened. Though young, she was very cunning, constantly excluding Bae-reum. One accident led to Soo-min being hospitalized, during which she accidentally overheard the doctor telling her mother: judging from the blood type, Soo-min was not Oh Chung-yeon's biological daughter! This shocking revelation made Soo-min more determined to drive Bae-reum away. In a scheme designed by Soo-min, she failed to harm Bae-reum but caused her beloved brother Myung-wi to be injured in a motorcycle accident, fortunately receiving help from Bae-reum, thus generating Myung-wi's affection for Bae-reum. After the plan failed, Soo-min framed Bae-reum, placing all the blame on her. Unaware of the truth, Wang Hyeok-yu was extremely displeased and suggested that Oh Chung-yeon send Bae-reum away immediately. Seeing Bae-reum about to be kicked out, Soo-min was thrilled but was saved by the timely arrival of Myung-wi. Myung-wi and Soo-min's families were old friends, and they had always had a good relationship since childhood, but now Bae-reum came between them. Seeing Brother Myung-wi increasingly neglecting her while protecting Bae-reum, Soo-min became envious and plotted a more unexpected action... Originally intending to teach Bae-reum a lesson, it resulted in her mother dying while rescuing Bae-reum. Filled with fear, Soo-min once again placed all the blame on the guilt-ridden Bae-reum. The grief of losing his wife made Wang Hyeok-yu... Thus, the natural father and daughter, Wang Hyeok-yu and Bae-reum, became entangled in an unresolvable grudge!
Fourteen years later, Bae-reum living in a village in Yunnan had grown into a warm-hearted and beautiful young woman, establishing a complex sibling-like relationship with Seo Jeong-bong. She took over Uncle's job, happily working as a bus driver every day, taking care of the villagers' travel needs. By chance, she met Myung-wi driving a car for inspection, yet they failed to recognize each other... Myung-wi, who was working in Shanghai, had just partnered with others to open a small company. Due to insufficient manpower, he urgently recruited Bae-reum to help. Determined, Bae-reum resigned from her bus driver job and excitedly boarded a train bound for Shanghai. Coincidentally, Myung-wi also unwillingly boarded the same train due to various accidents, and sat next to Bae-reum, leading to a series of awkward situations... Unexpectedly, soon after arriving in Shanghai, Bae-reum was embroiled in an economic fraud case involving Seo Jeong-bong's company. Seo Jeong-bong fled to avoid criminal charges, leaving Bae-reum to clean up the mess, but she refused to believe it was true. Could Seo Jeong-bong really do something illegal... One day, a group of employees from a company claiming to be extorted went crazy ransacking things at Seo Jeong-bong's company! Bae-reum thought the matter wasn't settled yet, so in anger, she rushed to the company to argue, only to unexpectedly find the boss was Myung-wi! Myung-wi was already overwhelmed with company affairs and couldn't tolerate Bae-reum's irrational behavior, leading to a heated argument. In a rush, Bae-reum, who knew judo, threw Myung-wi and got arrested, being sentenced for intentional injury...
After being released, Bae-reum couldn't find Seo Jeong-bong and, having a criminal record, was rejected by several companies, falling into hardship. Fortunately, two sisters she met in prison took her in. After many twists and turns, Bae-reum finally found a job as a driver. Little did she know it was also one of Myung-wi's companies. Once, Myung-wi needed to go out urgently, but his usual driver, Secretary Yang, was busy with matters for Soo-min, so he had to temporarily hire a driver, who turned out to be Bae-reum—truly "enemies meet by coincidence"! The strong-willed Bae-reum almost quit, but considering the reality of life, she endured without an outburst, though still tormenting Myung-wi on the road to vent her hatred! Soo-min accidentally learned about some incidents between them and arranged for Bae-reum to become Myung-wi's official personal driver, opening a new chapter of their overt and covert struggles…
Soo-min's family and Myung-wi's father were both old friends and important commercial partners. Under the guidance of the elders from both families, Myung-wi was forced to discuss marriage with Soo-min, who deeply loved him. However, by chance, Myung-wi discovered through a keepsake that Bae-reum was the little girl who saved him 14 years ago, reigniting his childhood affection for her! Out of protective feelings, he didn't reveal the truth but quietly began caring for Bae-reum, slowly changing their relationship, yet both kept these feelings buried deep inside... A woman's natural sensitivity made Soo-min realize the threat coming from Bae-reum, and she decided to drive Bae-reum away! Coincidentally, a self-proclaimed journalist named Lim Young-hwa came to Soo-min for personal gain. She was Jang Joo-jin's close cellmate who was imprisoned for fraud. She revealed the truth of Jang Joo-jin switching the babies years ago, proving with solid evidence that Soo-min was not Wang Hyeok-yu's biological daughter, and used it to threaten Soo-min... At this moment, Bae-reum happened to gain Wang Hyeok-yu's appreciation through a chance opportunity, was invited to his home as a guest, and was then entrusted with an important task by Myung-wi. Soo-min grew more fearful, wanting to protect her position in the Wang family and win Myung-wi's love. Reluctantly, she agreed to cooperate with Lim Young-hwa and placed her beside Bae-reum, creating various incidents to damage Bae-reum's image in the company; while intensifying the verification of Bae-reum's identity…
After much effort, Soo-min finally uncovered Bae-reum's true identity, making her restless... On one hand, she acted hurt in front of Bae-reum; on the other hand, she conspired with Lim Young-hwa to bribe Seo Jeong-bong to create a case causing significant losses to Wang Hyeok-yu's company, pushing the blame onto Bae-reum, while revealing to Wang Hyeok-yu that Bae-reum was the little girl responsible for Oh Chung-yeon's death years ago. New grievances piled on old ones, Wang Hyeok-yu, disregarding Myung-wi's desperate pleas, intended to sue Bae-reum. Helplessly, Myung-wi had to use "leaving Bae-reum and marrying Soo-min" as a condition to calm Wang Hyeok-yu's anger, abandoning the lawsuit...
However, on the grand wedding day, after much contemplation, Myung-wi left without a word, going to search for his true love, Bae-reum! Enraged by the loss of face, Wang Hyeok-yu retaliated commercially, quickly destroying Myung-wi's career, nearly plunging him into despair...
Encouraged by Bae-reum and friends like Seo Jeong-bong who had reformed, Myung-wi regained his spirit, gradually recovering and establishing a new company. Unexpectedly, just before the new company was about to open, Bae-reum suddenly fainted. Myung-wi then learned that Bae-reum had been diagnosed with leukemia, and her condition had worsened, requiring a bone marrow transplant as soon as possible...
However, the first match wasn't Myung-wi, but Wang Hyeok-yu! Since Myung-wi left her, Soo-min had never accepted it, feeling despondent every day, torturing herself. Wang Hyeok-yu saw this every day and felt heartbroken. Just then, he received news that Bae-reum needed a bone marrow donor. Thus, for the sake of his daughter, Wang Hyeok-yu once again proposed harsh exchange conditions to Myung-wi...
So, at the critical moment of Bae-reum's life, would Myung-wi compromise with Wang Hyeok-yu? Life is precious, could Soo-min withstand the moral condemnation and let her father make this deal? Would Soo-min reveal Bae-reum's true identity and the entire truth to Wang Hyeok-yu? Even if Bae-reum receives the bone marrow, would she truly be safe? What twists and turns will their fates encounter???