Based on a webtoon, "A Good Day to be a Dog" follows Han Hae-na, a high school literature teacher burdened by a peculiar generational curse. Kissing someone causes her to transform into a dog every night at midnight, returning to human form only at sunrise. The curse can only be broken if, while in her canine form, she receives a kiss from the exact same person. Hae-na desperately tries to avoid romantic entanglements to protect her secret, constantly dodging the advances of suitors.Tragedy strikes during a work dinner when a heavily intoxicated Hae-na confuses her stoic and aloof colleague, Jin Seo-won, for her crush, teacher Lee Bo-shum, and plants a kiss on him. Panicking, she flees, only to wake up the next morning as a furry terrier. To make matters worse, she discovers that Seo-won harbors a severe, paralyzing phobia of dogs, stemming from a deeply
traumatic childhood incident. Whenever she approaches him in her animal state to reverse the spell, he recoils in sheer terror, leaving Hae-na trapped in a nightly cycle of canine transformation.Determined to break the curse, Hae-na is forced to get close to Seo-won, engineering awkward scenarios to cure his dog phobia so she can safely receive the counter-kiss. As they spend time together outside the classroom, Hae-na begins to see past Seo-won’s prickly, cold exterior, uncovering a gentle, empathetic, and deeply wounded man. Concurrently, Seo-won finds himself inexplicably drawn to Hae-na’s warmth and resilience, slowly overcoming his lifelong trauma with her unwavering support.Their blossoming romance faces external threats and supernatural complications, notably from the school's seemingly mild-mannered history teacher, Lee Bo-gyeom. Bo-gyeom is actually a centuries-old mountain spirit harboring a dark, vengeful grudge against human royalty. He manipulates events, attempting to use Hae-na’s curse to ruin Seo-won, who is secretly the reincarnation of a historical figure tied to Bo-gyeom’s tragic past. Secrets unravel, and tensions peak when Bo-gyeom’s supernatural influence exposes Hae-na's secret to the entire school and places Seo-won in grave danger.Refusing to let dark magic tear them apart, Hae-na and Seo-won lean on their deep emotional bond. Seo-won confronts his past fears head-on, while Hae-na risks everything to protect the man she loves from the vengeful spirit. Ultimately, through genuine sacrifice,
emotional healing, and the power of true love, the centuries-old curse is completely shattered. Hae-na permanently retains her human form, and she and Seo-won cement their enduring romance, finally finding peace, redemption, and happiness together after a turbulent journey of magic and self-discovery.