Ban Ha-jin is calculating and ambitious. Even though he's an orphan and a high school drop out, he will use any means to fulfill his ambition. Through coincidence, he meets Yoon Jae-myung at a bar in Switzerland. Jae-myung is a popular former baseball player who went to the same high school as he did, and Ha-jin manipulates a series of events to become Jae-myung's best friend. He also runs into Oh Dan-hee, the girl he loved and hurt in high school.
Despite her painful childhood, Dan-hee grew up to be a tenacious, optimistic go-getter who dreams of becoming a world-class professional softball player. Although tormented from the memory of being humiliated by her ex-boyfriend Ha-jin, Dan-hee makes a pact with herself to move on. Her sports hero is Yoon Jae-myung.
After Switzerland, the three again become part of each other's lives back in Korea. Ha-jin starts working in Jae-myung's father's company and does everything to make the rich chairman like him, shrewdly climbing the corporate ladder until he becomes the boss's right-hand man. Dan-hee, who also works for the same company, is a softball player on the company's league team. Jae-myung becomes the team's coach, and he falls in love with Dan-hee whose headstrong and optimistic personality attracts him. Jae-myung tries every possible way to win her heart, as Ha-jin becomes torn between his ambition and his love for Dan-hee.
