You may kiss the bride . . . Clara and Koldo's wedding unfolds through the lens of a video camera that captures their beautiful ceremony and the festive reception that follows. But the camera also bears unblinking witness to the shocking reality of chaos and horror that ensues after a virus spreads through the reception, transforming the wedding guests into something inhuman, and forcing the newlywed couple into a terrifying fight for their lives. Separated amid the mayhem, the newlywed couple discover the true meaning of the vow, "'til death do us part."