Barnaby himself becomes the prime suspect when amateur photographer Lionel Bell is found death in the woods of Luxton Deeping because of a photograph showing Barnaby kissing Bell's estranged wife, who is an old girlfriend of his. Furthermore Barnaby's fingerprints are on a wine glass at Bell's home, an entry in Bell's diary names Barnaby as his guest the evening before his death and Barnaby has no alibi for neither that evening nor the time of the murder. The case is taken over by the unpopular detective inspector Martin Spellman who does not believe that the evidence against Barnaby is fabricated. More deaths occur while Barnaby conducts his own, unofficial investigation to clear his name.