Koldo and Clara are about to celebrate the most important day of their lives: their wedding. Everything appears to be running smoothly until some of the guests start showing signs of a strange illness. Before they know what’s happening, the bride and groom find themselves in the middle of a hellish ordeal, as an uncontrollable torrent of violence is unleashed on the wedding. What started off as an idyllic day quickly descends into a nightmare of the worst kind.