Skåne, 1986: On the night of Walpurgis, the eve of May Day, where bonfires are lit to ward off evil spirits and preparations are made to celebrate the renewal of spring, a 16-year-old girl is ritualistically murdered in the woods beside a castle. Her stepbrother is convicted of the terrible deed and shortly after, the entire family vanishes without a trace. Spring, 2019: Dr Thea Lind moves into the castle. After making a strange discovery in an ancient oak tree on the grounds, her fascination with the old tragedy deepens. As she uncovers more and more similarities between her own troubled past and the murdered girl, she begins to believe that the real truth of the killing was never uncovered. What if the spring of 1986 claimed more than one victim?