If you've seen a brainwashed secret agent in fiction recently, it probably owes a lot to The Manchurian Candidate, the Academy Award-winning 1962 film based on the novel by Richard Condon. As great as the film is, the greatest character in it is Angela Lansbury as Eleanor Iselin.
For those of us who grew up when Lansbury was Mrs. Potts and Jessica Fletcher, watching The Manchurian Candidate will cause some severe cognitive dissonance. She's brilliant and terrifying. She's the real mastermind of this whole plan, and nothing is scarier than the idea that she might succeed.
Mrs. Iselin is a woman a communist agent — as is always the case in Cold War era spy novels — who has married into a prominent right-wing family to further her agenda. The McCarthy-esque man she marries is her son's stepfather, just another cog in the plan, and her son's role is to be feted as a war hero and be brainwashed into becoming a sleeper agent.
Her goal is to get her husband the presidency, where she can manipulate everything as part of an international communist conspiracy. This plan? Involves programming her brainwashed son to a) kill the man standing in her way — incidentally his stepfather and he kills his wife when she gets in the way and b) kill the presidential candidate so that her husband, the vice presidential candidate, will take over his role and, on the sympathy vote, win. Mother of the year!
It does not matter at all that Lansbury is only three years older than the man playing her son. She's perfection in this part:
Now, go watch Beauty and the Beast. You'll never see Mrs. Potts the same way again.