Originally set to be directed by Don Siegel but credited to TV director William Wiard (although rumoured that star Steve McQueen directed much of it) it can only be guessed at what Siegel would have done with this. Whilst McQueen is interesting in the lead role the film sort of plods along rendering it a mediocre addition to the cycle of historical westerns that emerged in the mid 70s to mid 80s. Based on the true life of the title character, a former tracker, Indian fighter and scout who drifts into Wyoming at the turn of the 20th Century and is hired by a cattleman's association to hunt down rustlers plaguing the territory. Horn proves just a little too good at the job and so is framed for a murder so as to get rid of him. There's no heroism on offer here, it's a tale of an assassin devoid of morality who sees his job as basically murdering the opposition of the corrupt group of ranchers who hired him. There's a half baked romance with a school teacher (Linda Evans) pointlessly thrown in probably to give McQueen's character some softer edges for the audience. The film sets itself completely into the camp that Horn was set up and innocent although historically there are differences of opinion. As McQueen's penultimate film, and made while he was seriously ill with cancer, it's a competently made and interesting western but it's far too unstructured and meandering to rank with other similar films of this type and period. There's some good western character actors in support roles including Slim Pickens, Elisha Cook Jr, Richard Farnsworth and Roy Jenson.