Michael Clayton begins with a series of night shots passing over and through the office towers of Manhattan. As the camera presumably presents the audience with the faceless centers of commerce and law, a voiceover spoken through a phone with the clarity of a manic-depressive on a high accompanies the passing corporate vista. The voice belongs to Arthur Edens (Tom Wilkinson) and here’s part of what he has to say: “I realized, Michael, at that moment, that I had emerged — as I have done nearly every day for the past 28 years of my life — not through the portals of our huge and powerful law firm, but rather from . . . an organism whose sole function is to excrete the poison — the ammo — the defoliant — necessary for even larger and more dangerous organisms to destroy the miracle of humanity.”

Eden’s convoluted yet intensely clear monologue sets both the high pace and tension of the film right from the start – and it doesn’t let up. But it is Michael Clayton’s central theme, power and the lengths people will go to maintain it, that makes the film an anxiety-ridden meditation on corporate life and the price it exacts from its participants.

As lead defense counsel for agribusiness giant UNorth fending off a massive class action lawsuit, Edens discovers he has been on the wrong end of a fight after 16 years of litigation. Foregoing his medication (Edens suffers from bi-polar disorder), he has a manic episode during an on-camera discovery meeting. Naturally, the corporate brass at UNorth are freaked out. Fearing the loss of a client with very deep pockets, Edens’ firm sends out “fixer” Michael Clayton (George Clooney) to the hinterlands of America to bring their top defense attorney to heel. But in the end it is not Edens’ erratic behaviour that frightens UNorth, it is the fact that Edens is in possession of documents that prove his client to be an unethical, indeed downright evil organization.

Michael Clayton could easily have been played as a good versus bad morality tale along the lines of a David Grisham legal thriller, but the conflicted natures of the central characters consigns the film’s moral center (if it even has one) to a permanent grey zone.

None of the main characters are presented as a foil for the others because all of them have been slogging it out in the same moral vacuum, it seems, for decades. Clayton himself, the film’s under-hero and played with a broken dishevelment by Clooney, has spent a career fixing the “mistakes” of a certain class of people with the money to pay for his services; while head counsel for UNorth, the seemingly cold and calculating Karen Crowder, performed as though she were on nothing but a diet of ice cubes and speed by Tilda Swinton, seems to act out of desperation at the behest of her corporate overlords rather than from any psychopathic intent.

Despite one plot oversimplification and an ending bordering on the melodramatic, Michael Clayton, saved by its exploration of moral ambiguity, remains a superb film about the damage caused by the pursuit of wealth and power. But given that Edens — who himself is inextricably linked to the same regime of greed that his clients are committed to — is able to acknowledge that he has been serving an “even larger and more dangerous organism,” suggests a moral victory no matter how difficult Michael Clayton makes it to find.