. On a rainy night, a driver attempts to stop taking passengers and changes his sign to "not in service," but events take an unexpected turn, leading to a mass casualty event. Defining "Limbo" : Through the narration of nurse

: Episode 5 provides the essential backstory for the series by revealing a tragic bus accident

The series premiered in late 2024, with Episode 5 airing as part of the mid-season rollout.

: A couple (the "woman in red heels") who had just had a heated argument about their relationship. Hyun-ju and her Mother : Heading home together when the accident occurred. The Witness

As Lee Ji-young watches from a distance, the bus's brakes fail, causing it to crash through a bridge and plunge into the river.