Another violent adventure for self-deprecating, tough-as-nails exactor turned P.I. Mark Savage (Malice in Camera, etc.). Anthony Raven, son of super-rich industrialist George Raven, son-in-law of retired Detective-Inspector Sam Birkett, CID, has been kidnapped and his best friend Geoffrey Earnshaw murdered. Sam asks Mark, a longtime friend, for help in delivering the ransom and maybe tracing the kidnappers--a group calling themselves S-W-A-L-K, with vague terrorist connotations. The ransom, in diamonds, is hair-raisingly collected in late-night Covent Garden, with no sign of Anthony's release. Instead, the gang members are killed, one by one, as Sam and Mark stay one step ahead of the authorities in their search for Anthony, dead or alive, and in their slow, life-threatening penetration into the heart of the scheme and its deranged, wily perpetrator. The affectionate, unsentimental mutual respect of this unlikely duo makes for great teamwork--and the author's style is swift, zingy and faintly ironic. By the close, the story has built to a tingling climax that leaves the reader sorry it's all over. Payne's best to date.