Rhysand's sister is alive. It has been a year of peace since the defeat of Queen Briallyn, but darker forces are still at work. Callisto is brought back to life through the magic of the Cauldron, but she is unable to step foot outside the borders of the Spring Court. Tamlin suddenly finds himself with the unexpected-and unwanted-task of looking after her. Wanting to escape their current predicament, the two of them concede to work together to find a solution to their problem. As they try to figure out how to lift Callisto's curse, they also navigate the complicated waters of guilt and past traumas. Will the Lady of Night and the Lord of Spring finally find common ground, or will the feud between the two courts continue?