Happiness is one of those rare K-dramas that uses a fantastical premise to say something deeply human. Set in a near-future South Korea where infectious disease has become the new normal, it blends zombie-thriller tension with a sharp commentary on class, survival instinct, and human selfishness — all wrapped in an unlikely love story. The title is intentionally ironic: in this world, happiness is the one thing hardest to hold on to.
The series takes place in a time when infectious diseases have become the new normal. A failed treatment drug called “Next” has triggered a worldwide pandemic known as the Lytta Virus — nicknamed “mad person disease” — which causes the infected to experience short bouts of insanity and bloodlust before fully regressing into a zombie-like state.
The story is largely confined to a newly built apartment complex, where residents — locked down and cut off from the outside world — must navigate the dual threat of the infected and each other. Think less Train to Busan, more Parasite with zombies.
Yoon Sae-bom (Han Hyo-joo) is a sassy, capable anti-terrorism trainer with dreams of moving into a nice new apartment — one that requires applicants to have enough “points” to qualify. She ends up marrying her childhood friend Jung Yi-hyun (Park Hyung-sik), a detective and former baseball player, in a marriage of convenience so they can co-own the apartment.
When Sae-bom encounters a trainee infected by the Lytta Virus and is scratched during the struggle, she meets the mysterious Han Tae-seok at a research facility — a government figure with his own agenda regarding the cure. Once the apartment complex is placed under quarantine, the real drama begins: the show brings out many versions of humanity — those who help selflessly, those who save themselves first, and those who believe money can buy anything, even in an emergency.
Best suited for:
May not be for you if: You’re expecting non-stop zombie action — this series is more focused on investigation and interpersonal thriller elements, with less violence and more story depth
Happiness is an ambitious, genre-blending K-drama that succeeds more than it stumbles. It’s not a pure zombie horror — it’s a character study wrapped in an apocalypse, asking what people are really like when the walls close in. The central couple is magnetic, the social subtext is sharp, and the atmosphere is consistently gripping. The final episodes do feel slightly rushed, and some side characters test your patience, but the overall package is absolutely worth your time.
Verdict: 8/10 — A must-watch for K-drama and thriller fans alike. Don’t let the zombie premise fool you; this one’s really about people.