Photograph taken at murder scene, camera tossed from castle lands in chemist John Gray's car. After developing film, he becomes amateur sleuth seeking woman in photograph, investigating murder as evidence.

When a photograph is taken at the scene of a murder, the camera is tossed out of a castle window to destroy the evidence and lands in the back of a passing car belonging to chemist John Gray who becomes an amateur sleuth after developing the film, and goes in search of the woman captured by the photograph.