Shin Woo Yeo, a 999-year-old nine-tailed fox disguised as a charming writer, needs human energy stored in a magical bead to finally become human.

When college student Lee Dam accidentally swallows his bead during a bizarre encounter, their fates become entangled. The bead can only stay inside a human for one year before it shatters—killing the host. To protect her and preserve his dream, Woo Yeo proposes they live together until they find a solution.

Now, Lee Dam—who's never even had a boyfriend—must share her life with a mystical fox who may just steal her heart.