"Oppenheimer" tells the story of the US-american theoretical physicist J. Robert Oppenheimer, beginning at his time as a student and spanning all the way till the end of his life, when he got discredited as a communist by high-ranking politicians during Mccarthyism.
The movie mixes two timelines.
The first one portrays Oppenheimer's carrer as a student, physician and later as head of the Manhattan-project resulting in the fist detonation of an atomic bomb. At the same time he and his wife Kitty Oppenheimer have to grapple with their past when both of them had contact to American communists, resulting in the accusation to be communists themselves. Those sequences were shot in color only.
The second timeline portrays Oppenheimer's conflict with US-american politician Lewis Strauss, who is suspicious of Oppenheimer discrediting him - the prevented physician - in front of Albert Einstein. Thereupon Strauss starts a vendetta ending in Oppenheimer's dismissal from the Atomic Energy Commission founded in 1946. In the process he utilizes Oppenheimer's and his wife's contacts to American communists, Oppenheimer's engagement against an arms race between nations and his disapproval towards the developement of a hydrogen bomb to depict him as a sympathizer and supporter of communism. Politically ruined Oppenheimer is fired from the Atomic Energy Commission. Strauss' behavior fires back when he has to give testimony in front of congress to be nominated for Secretary of Commerce what due to the testimony of former colleagues of Oppenheimer, enraged by his dismissal, turns into a disaster. Those scenes were exclusively shot in black and white.
In fact Einstein's gloomy mood, he shows towards Strauss, has a different reason: During a chat at a lake, Oppenheimer confronts Einstein with the works of his colleague Edward Teller which suggest that the detonation of an atomic bomb may set the atmosphere on fire and thereby obliterate any life on earth. In a melodramatic scene Oppenheimer utters his apprehension, that he might have obliterated planet earth, even though he has not set the atmosphere on fire. Nevertheless Oppenheimer experiences his political rehabilitation by John F. Kennedy whose successor Lyndon B. Johnson awards him the Enrico-Fermi-Prize, which is awarded for bleeding-edge research around the topic of nuclear physics. Mentally Oppenheimer - psychologically instable since his time as a student - is haunted by visions of a planet scarred by nuclear bombs.