April 1943: four boys playing in Hagley Woods, Essex make a gruesome discovery. Inside an enormous elm tree, there is the body of a woman, her mouth stuffed with a length of cloth. As the case goes cold, mysterious graffiti starts going up across the Midlands: 'Who put Bella in the Wych Elm?' To Ross Spooner, a police officer working undercover, the messages hold a sinister meaning.
