Lee Young-joon's family runs a large company and he works as the vice-president of the company. He is smart, rich and handsome, but he is arrogant. His secretary is Kim Mi-so. She has worked for him for years and she is perfect for him, but Kim Mi-so decides to quit her job.

When a high school diploma becomes the key to unlocking his inheritance, a spoiled teen gets an invaluable lesson in life and love in a rural village.

Despite their different family backgrounds, four friends grew up together in the wearisome years of the 70s. But as time goes by, each of them takes a different life path.

Tae Ho and Sang Goo are two men who constantly fought at work and hates each other even more now that they’re both the heads of rival companies. When their children Do Hee and Young Joon get married, the bickering fathers are forced to become in-laws.

Jeong-woo, who grew up with Han-na under their adoptive mother, goes abroad to contribute to a difficult family environment. However, after hearing the news of the death of his adoptive mother in a hit-and-run traffic accident, he returns to Korea, and found out that Cheol-jin, a member of the local organization Taechangpa, and former classmate of Han-na was involved. Meanwhile, Taechangpa joined hands with the Japanese yakuza organization to expand its power. They kidnapped Han-na to catch Jeong-woo, who was tightening them up. This makes Jeong-woo even angrier. The anger of a man who lost everything explodes!