When the snow thaws on London's Hampstead Heath after a harsh winter, a ghoulish discovery is made that marks the start of a very dangerous case for Detective Inspector Harry Vicary and his team. A body of a man is found on top of a shallow grave containing the battered remains of a young woman. He appears to have frozen to death, but what is his connection to the remains below? Vicary's investigation leads him deep into London's criminal underworld.