"Despite her impressive qualifications and a degree from a prestigious university, Kang Yoona is struggling to find a job. Frustrated after sending out countless resumes, she decided to indulge herself (if you know what I mean). But as she finished, she found a strange man staring back at her. The man, Kyle, turned out to be the CEO of a start-up in the underworld, and Yoona unexpectedly ended up working there on a short-term contract. On her first day, Yoona and Kyle encountered each other at a mysterious hot spring in Ulcheon Mountain, deep in the heart of Hell... "