耄耋之年的撒切尔夫人（梅丽尔·斯特里普 Meryl Streep 饰）罹患老年痴呆症，时常在幻觉和回忆中切换。她感觉深爱的丈夫一直在身边陪伴，其实后者早已亡故。她作为杂货店的女儿，因为出身贫寒，时常饱受世人的白眼。然而，在聆听了保守党的演讲后，她坚定了自己的政治信仰，并以优异成绩考入牛津大学，虽然在一次议员选举中落败，但是她却收获了真挚的爱情与他相伴，坚定了自己从政的人生道路……选段中，撒切尔夫人在执政11年之后，她手下的议员渐渐背叛了她，想要推翻她的政府，而撒切尔夫人也不得不发表辞职说明……
News：Will she, or will she not, be in the job tomorrow?
Official：Margaret, they can't touch you.
News：Mrs Thatcher has failed to win enough votes to secure an outright win in the leadership contest and must now decide whether to put her name forward for the second round.
News：As Mrs Thatcher leaves Paris for London to make a last ditch attempt to pull together support for her leadership, the ship may have sailed.
Official 1：We will never win another election led by that woman.
Official 2：We need a leader who listens. This isn't about her, it's about the party.
Official 3：One must know when to go. The question is, how does anyone put it to her?
(In The Office)
Official 1：If you were to stand, I of course would vote for you Prime Minister.
Official 2：Of course would vote for you Prime Minister, but I don't think you can win. The loyalty of my colleagues cannot be counted upon.
Margaret：It was the people who put me here.
Official 1：The loyalty of my colleagues cannot be counted upon.
Margaret：It's up to them to tell me when to go.
Denis：Margaret, you can't let them do this to you. Please, boss. They'll destroy you. Throw in the towel now, love. Don't let those bastards see you humiliated. You just won't win, darling. Not this time.
Margaret：Oh Denis. I am the Prime Minister.
(In The Debate)
Margaret：The Right Honourable gentleman is afraid!
Official：This is a naked strategy of closing some coal mines and then selling off.
Margaret：They believe in striking. I believe in working!
Official：This is the woman who's watched ten men on hunger strike starve themselves to death and never flinched!
Official：More homeowners, more shareholders, more savings...
Margaret：I offer my resignation after eleven and a half extraordinary years proud to have left Britain in a much better state than when we took office. What's this then? A radio. How useful. Steady, MT.