While haunting her usual subway car one day, lonely ghost Park Ja-eon receives a chance from a deity to redo one year of her life and earn a spot in eternal paradise. With the aid of a grumpy divine guardian and a newfound ability to see ghosts, Ja-eon restarts her senior year of high school. As the unlikely duo ends up helping spirits and humans alike, they begin to reflect on their own relationships and regrets. But with the clock ticking on Ja-eon’s second shot, is there time to set it right?