Kang Do-hyun chooses an ordinary life as a taxi driver to avoid inheriting his father’s family business. One day, he happens to rescue Cha Eun-seol, who is fleeing a chase and has accidentally taken the wrong medication. After a one-night encounter, they part ways and return to their separate lives.
Four years later, a stylish CEO shows up with a child and proposes marriage to Do-hyun. After registering their marriage, Eun-seol faces pressure from her parents to abandon the child, but Do-hyun appears and protects both mother and daughter.
As her company falls into crisis, Eun-seol attends a family banquet of Taegang Group—the most powerful conglomerate in Country A—to secure a 10-billion-won investment, unaware that the chairman is actually her husband’s father. At the banquet, despite pressure from her former fiancé Gu Jung-tae, Do-hyun’s father protects his granddaughter Kang Rumi and makes his presence known, yet he can only approach her as a “grandfather” without revealing his true identity.
As time passes, Do-hyun and Eun-seol grow closer. However, after failing to secure investment, Eun-seol risks both her company and her board position by making a dangerous bet with her father, Cha Myung-hwan. At this critical moment, Do-hyun seeks out his father, accepts the responsibility of becoming the heir, and begins to take action himself.
In the end, at a press conference, the capital and influence Do-hyun has prepared turn the situation around. Eun-seol not only saves her company but also secures full ownership, achieving both love and success.
