"Sinkhole" is about what happens when a newly built villa falls into a sinkhole with its residents trapped inside. The residents’ families and emergency services attempt to save them. The main character, Park Dong Won is a man who finally buys his home after 11 years, only to have it fall into a sinkhole within a minute. Along with Dong Won, there's also Kim Seung Hyun, who ends up getting stuck in the sinkhole with him, who is his supervisor at work.
With them is also the Chungwoon Villa resident, Jung Man Soo, who works multiple part-time jobs to raise his son as a single dad.