What deep, dark secrets are hidden in the diary? Seo Ji Yoon is a modern-day art history professor who happens to stumble upon the secret diary of Shin Saimdang (1504-1551), a Korean artist, writer, calligraphist and poet who was the mother of Yi I, one of the two most prominent Korean Confucian scholars during the Joseon Dynasty. The diary sheds new information on the life of Saimdang and her relationship with Lee Gyeom, a painter, calligrapher and musician who was a childhood sweetheart and soulmate of Saimdang. Will the diary help Ji Yoon unravel the mysteries surrounding a painting of an unknown woman from the Joseon Dynasty?