Free-lance adventurer Raven--trendy as ever, living on his Thames houseboat, jogging, listening to Bach, growing flowers on his deck--is back, and his new case again manages to become part of his crusade against corruption at Scotland Yard, his onetime employer. A young Canadian convicted of theft has committed suicide in jail, and his sister enlists Raven to help prove a frame-up. She also appears to be Raven's Miss Right, and their unconvincing romance consumes an ordinate amount of space here. Still, Raven does the job--by getting the goods on a rather engaging professional informer and tracking down an ambitious upper-echelon policeman--and there's some okay action along the way. But the suspenseless Scotland-Yard vendetta has grown wearisome, and, with that goopy romance and lumpier-than-usual prose, this is second-rate MacKenzie for devoted Raven-ers only.