isn't a western, as might be gathered, but a drug-ring melodrama. David McCallum shows up early in the film as a spaced-out junkie. But fans need not worry: McCallum is actually an undercover agent, looking for the source of heroin being trafficked by the Mafia. The top man in the Mexican-based narcotics operation is the man you'd least likely expect -- especially when one remembers the sort of roles the guilty party had previously played in his long career. Based on Robert Wilder's novel , this went out to British moviehouses under the title .