When human remains were found hidden in a hollow tree during WW2, one of the UK's greatest murder mysteries was born. This documentary explores Nazi Espionage, Witchcraft and the Supernatural in an attempt to finally piece together this sinister jigsaw puzzle once and for all. With previously classified MI5 information now available and people breaking their 75 year silence maybe the mystery of "Who put Bella in the Wych-Elm?" can finally be put to rest?