An insurance company, quite unwilling to pay out a load of money to beyond the law multimillionaire Curt Valayan (John Gielgud) for the "accidental" sinking of a few ships that left twenty-eight dead bodies behind, hires cynical investigator Richard Cutting (Patrick O'Neal). The company hopes that Cutting will be able to find information Walter Green, a man formerly in the employ of Valayan's chief of illegalities Matt Wilson (Herbert Lom), may have left behind when he died in a plane "accident" over the Swiss Alps just before he could sell off said information to them.
Cutting quickly finds out that Green isn't as dead as everyone expected, and seems to have fled to his native Zürich, where he now has been hiding out for six months. Unfortunately, Wilson realizes this interesting fact at about the same time Cutting does, so it becomes a race to find Green and get him to - respectively - cooperate or murder him. Cutting's efforts are supported by Dominique Laurant (Joan Hackett), Green's former part-time secretary who helped him out with the hiding business without ever realizing what her boss was involved with. Dominique, a young woman with moral principles and a thing for a cynical old freelancer, might be able to break through Cutting's amoral shell, and drive him to do something good for once in his life, but when has that sort of thing ever been healthy for a woman in a movie like this?
Despite not featuring any actual spies, Sheldon Reynolds's Assignment to Kill is very much a spy movie, and one closer to the less silly Eurospy films than James Bond to boot. In place of professional spies, the film features various freelancers working a dirty business that is a lot like your usual spy game, and whose morals are just as fluent and ambiguous as those found in the more earnest spy movies. Interestingly, the characters "in the know" are talking about post-national spy politics before those were very much in vogue in the genre. It's only 1968 (and you'll know it) but patriotism is already no excuse the characters in this movie are willing to use for doing horrible things to innocents and each other; they do it for money, or because it's the only thing they're good at, or just because they never bother to think about the moral implications of their actions.
Given this - depending on one's tastes either bitter or honest - view of affairs it's neither a wonder nor much of a surprise the film's only character with uncompromised morals has to die to give Cutting some of his sense of justice back. Which he then proceeds to defend with the same mixture of lies, violence and betrayal he uses in less worthy causes - and that's without interpreting the film's final act exclusively as very personal vengeance that uses justice only as a pretext.
With this less than bright and shiny text and subtext, it may come as a bit of a surprise that Assignment's tone is quite a bit more chipper than one would expect. There's more dry humour than bitter tears on screen. The interplay between O'Neal and Hackett fluctuates between sarcastic repartee, surprising tenderness and hints of actual emotional complexity, and stands out as a particularly - and surprising - human relationship that counteracts what could be an exercise in nihilism. Of course, the film at hand is still pretty cynical once you think about it: after all, Cutting may have taken down the bad guys in the end, but Dominique is still dead, Cutting's methods are still the same they have always been, and the world won't change just because three particular bastards haven't any power in it any more.
What makes Assignment work as well as it does, though, is how little it tries to push these darker elements of its script at its audience. They are there when you're willing to think about what you are seeing, but they never try to take control of the movie's surface. This surface is that of a very well made semi-Eurospy movie made in the US, with some decent action scenes, quipping characters, many well-constructed moments of suspense, and a rhythm that's as snappy as anything you'll find in the genre.