Karen Crowder is a neurotic, career-obsessed business executive for the immoral pesticide corporation U-North. Karen orders the assassination of a potential whistle-blower who found out that U-North was selling a known carcinogen, the assassination is made to look like a heart attack. The titular character, Michael Clayton is friends with the assassinated would be whistle-blower is not convinced, he quickly starts to pick up the trail. Karen Crowder decides to dispose of Michael Clayton as well.
After Karen's plans to assassinate Michael Clayton fail, she is confronted outside of a board meeting, where U-North is on the verge of settling their carcinogen issue. Clayton chastises Karen for not bribing first. Karen who is extremely flustered loses her cool and offers Clayton a bribe of 10-million dollars. Clayton tells her that she has been setup and was being recorded and snaps a picture of her face just as the realization has hit her. Faced with a long prison sentence, her cherished career obliterated and the company she worked so hard to protect in jeopardy of disintegrating because of her own foolish actions.
An excellent YouTube video highlighting Karen's downfall and Swinton's excellent acting exists.