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?

The reigning queen orders the killing of her stepson in order to continue her family's ability to take control over the kingdom. Yeon Woo, who happens to hold the position of the crown princess, suffers an illness that leads to her alleged death. Now, it's up to the King Hwon to decipher the truth, and put an end to the wars that wrath over the kingdom.