Forensic mechanic Helena Rutherford is investigating a serial arsonist targeting young women when her own house is set ablaze, trapping her inside. Officer Trevor Slate and his K-9 partner, Lark, arrive just in time to save her from the flames. But the discovery of her missing best friend's bones among the ashes upends everything, drawing them into a puzzling cold case. With a dangerous killer on their tail, Helena and Trevor must unravel the mysteries of both cases before she becomes the next victim.