Shin Woo-yeo is a 999-year-old gumiho, a mythical nine-tailed fox, who has spent centuries trying to become fully human. To achieve this, he must collect human energy into a magical marble. Time is running out, as he only has a short window left before he turns into a malevolent goblin. Meanwhile, Lee Dam is a fiercely independent, modern university student who has never been in a relationship, prioritizing her studies and personal boundaries above all else.Their lives collide catastrophically one fateful night when a heavily intoxicated friend of Dam collapses onto Woo-yeo, who is walking by. During the commotion, Woo-yeo’s precious marble falls from his mouth. Before he can retrieve it, Dam trips and accidentally swallows the glowing artifact. Panicking, Woo-yeo reveals his true
supernatural identity and explains that the marble will kill a human within a year. Since removing it immediately is impossible, Woo-yeo insists that Dam move into his traditional Korean home so he can monitor her health and figure out a way to safely extract it.Initially, the arrangement is fraught with tension and comedic friction. Dam resents having to alter her lifestyle, while Woo-yeo struggles to adapt to the chaotic energy of a twenty-something college student. However, as they navigate daily life together, boundaries blur. Woo-yeo’s stoic, protective nature begins to melt Dam’s skepticism, and she finds herself drawn to his profound depth and quiet kindness.Complications arise when a wealthy, narcissistic campus playboy named Gye Sun-woo sets his sights on Dam. Simultaneously, Yang Hye-sun, a reformed gumiho and Woo-yeo’s longtime friend, enters the picture, bringing her own brand of modern romance drama alongside Do Jae-jin, Dam’s loyal and naive best friend. As rivalries and friendships develop, Woo-yeo notices unexpected emotional changes within himself: he is actually starting to feel genuine warmth and affection, sensations that were previously foreign to his immortal existence.As the year draws to a close, a darker truth comes to light. The marble’s condition is tied to human emotion; the more connected Woo-yeo becomes to Dam, the more the marble changes. This puts Woo-yeo in mortal peril, forcing him to choose between completing his
transformation into a human or sacrificing his existence to save the woman he has grown to love. Through harrowing supernatural trials, deep emotional sacrifices, and romantic tension, both characters must fight against the cruel whims of fate to secure a future together.