Once a popular girl, Hye Jin grew into freckles and curly hair, losing the perfect features she had during childhood. Sung Joon, who used to be chubby and fainthearted, grew up into a successful and perfect looking guy. Ha Ri, the girl who seems to have everything, lacks some sex appeal. Shin Hyuk is a guy with regurgitative humor who has something to hide. Hye Jin and Sung Joon had a crush on each other back in childhood, but He and his family moved to the states. After many years have passed, Sung Joon came back to Korea as a fashion magazine chief editor while Hye Jin was still jobless. He wishes to meet Hye Jin after his return.

Ha Ryu is a prosecutor in charge of a corruption scandal of the first lady, Joo Da Hae. He's an orphan, and he wasn't living such a decent life in the past. But he had Da Hae by his side, and they were a happy family, including their daughter Eun Byeol. Da Hae also had rough times when she couldn't even afford her mother's funeral. Because of the painful memory from the old days, she gets ambitious for the upper crust, eventually marrying Baek Do Hoon of Baekhak Group. As Da Hae awakens her ambition to join the high class, she betrays Ha Ryu, making him fall into the bottomless pit. He starts his new life as his twin brother Cha Jae Woong and gets down to his revenge on Da Hae.

In present-day Seoul, architect Lee Seung Min (Uhm Tae Woong) is unexpectedly visited by his first love, Yang Seo Yeun (Han Ga In), whom he hasn't seen in years. While Seung Min (Lee Je Hoon) and Seo Yeun (Bae Suzy) shared a connection in their college architecture classes, unspoken feelings and missed opportunities led to their separation. However, Seo Yeun is approaching him in a professional capacity: she wants to hire him to help rebuild her family home on Jeju Island. While he's initially hesitant and has difficulty coming up with a design that Seo Yeun is satisfied with, Seung Min eventually agrees, resulting in Seung Min and Seo Yeun spending a lot of time together – to the growing annoyance of Seung Min's fiancée Eun Chae (Go Joon Hee). Will this project result in Seung Min and Seo Yeun getting back together, or will they put their past to rest for good?

Woo Ri, an intelligent 9-year-old girl, never knew her father's name. She stands by her deaf mother's side with Young Gyu, a not-so-smart man who falls in love with her mother, and Ma Ru, his son. A man who hopes to inherit his grandfather's company running by his stepfather named Dong Joo meets Woo Ri years later. He teaches her how to play the piano. In a world of uncertainties, the two now learn to listen to each other's hearts while plotting revenge against Dong Joo's stepfather.