Margaret Thatcher (Meryl Streep) to kobieta, która postanawia przebić się przez barierę płci i klasy. Pragnie zwrócić na siebie uwagę w zdominowanym przez mężczyzn świecie. Bohaterka jednak aby dojść do władzy musi zapłacić za to wielką cenę. Intymny portret jedynej dotychczas kobiety, która kiedykolwiek wybrana została na przewodniczącą partii rządzącej Zjednoczonego Królestwa.
Elderly and a virtual prisoner in her own home due to her concerned staff and daughter Carol, Margaret Thatcher, Britain's first woman prime minister, looks back on her life as she clears out her late husband Denis's clothes for the Oxfam shop. Denis is seen as being her rock as she first enters parliament and then runs for the leadership of the Conservative Party, culminating in her eventual premiereship. Now his ghost joins her to comment on her successes and failures, sometimes to her annoyance, generally to her comfort until ultimately, as the clothes are sent to the charity shop, Denis departs from Margret's life forever.
