What we know:
1. In episode two, Goo Ryun was shown to have journeyed endlessly through hell and refused to give up until the King herself arrived to take her away and beg her to save someone who desperately needed saving. Ryeon is still unsure of the person's identity, and if the mission fails, she will be forced to return to hell and resume her roaming.
2. Based on the hints Goo Ryun most likely committed suicide hence why she ended up in hell.
3. In ep 5it has been confirmed that Joon Gil and Goo Ryun were most likely lovers in the past. Would explain why Joon Gil feels so strong about suicide
4. In ep 5 we see also see a scene where she is fighting with someone, yet we never actually see the face just that it most likely a male.
That make me wonder what's the link between Joon Gil and Goo Ryuns suicide, and how is Joon Woong tied into all of these or is he even tied to their past? Why did she commit suicide and who must she save. Is it Joon gil, Joong Woon, herslef or is it another person that hasnt been revealed? What makes that person special and are they connected to her past and possibly her suicide? Is that person special because she has strong feelings of either hate or love toward them?