One tranquil summer, a mysterious woman checks into a vacation rental — triggering events that disrupt the lives of the owner and those around him.

In a dystopian 2071 devastated by air pollution, the survival of humanity depends on the Black Knights — and they’re far from your average delivery men.

Yeon-du asks her best friend Bora to collect all the information she can about Baek Hyun-jin while she is away in the U.S. for heart surgery. Bora decides to get…