Yeok, a middle-aged teacher raising a son and a daughter alone, witnesses students fall to their deaths from the rooftop of the school where she works. Discovering that her daughter Hyejeong was also present at the scene, she presses her for answers, but Hyejeong only repeats the same words: 'There was a bird in the sky.' As the strange, unexplained deaths continue, Yeok, together with a reporter covering the case and a streamer who runs a birding channel, head towards the birds’ habitat.

High school teacher Gyeongseok agrees to look after his daughter Yunhui for his ex-wife’s sudden request. He brings Yunhui with him to the school where he works. There, he leaves Yunhui alone in the car briefly, and when he returns she’s gone. Later, Yunhui is found after having been grievously injured in a car accident. The driver of the truck that hit her, however, indicates that Seik, one of Gyeongseok’s students, was the true cause of the accident.

One day, three siblings receive a postcard from their mother who left them a long time ago. But all it says is "I miss you." Three siblings are disconcerted by the sudden contact, but eventually, they go on a trip to meet their mother.

This drama tells a story that happened in an ordinary village in which a missing case occurs on the day of a wild boar hunting and the secrets of the villagers surrounding the case are being unfolded one by one.

The story follows five friends in high school who receive a death warning from a mysterious wish-granting app. As they struggle to escape their fates, they uncover chilling truths that connect the app to the sudden death of a classmate.

Days after her friends disappear during a trip to a mysterious cave, a girl is approached by a grown man claiming to be one of her missing pals.