The brutal murder of a woman in a lonely beach cottage, huge footprints found nearby, a meandering tramp singing snatches of opera in the night! Superintendent Minter - "Sooper", rattles around the countryside on his noisy motorbike and tries to find a connection. Hampered by amateur detective Gordon Cardew, aided and admired by lawyer Jim Ferraby and the beautiful Elfa Leigh, Sooper finds the case further complicated by another murder. The mysterious 'Big Foot' anticipates Minter's every move and only by delving into the past does he solve the case and bring the villain to justice.