Ai-oon's identical twin Ob-oom is in a tragic accident the night of her wedding. Ob-oom survives but is left in a coma and her husband doesn't make it. Helpless to do anything for her sister, Ai-oon resolves to do her the favour she'd refused hours earlier. This leads her to a woman she could not have prepared for her, a woman she finds herself drawn to even as she questions whether she could have been involved in Ob-oom's accident. (Source: MyDramaList)