In 1959, Truman Capote learns of the murder of a Kansas family and decides to write a book about the case. While researching for his novel In Cold Blood, Capote forms a relationship with one of the killers, Perry Smith, who is on death row.
Famed writer Truman Capote, southern born and bred but now part of the New York City social circle, is growing weary of his current assignment of writing autobiographical type pieces for the New Yorker. After reading a newspaper article about the just occurred November 14, 1959 cold blooded murders of the Clutter family in their rural Kansas home, Truman feels compelled to write about that event as his next article. So he and his personal assistant Nelle Harper Lee, also a southern born New Yorker and an aspiring writer of her own, head to Kansas to research the story first-hand. Truman hopes to use his celebrity status to gain access to whomever he needs, such as to Laura Kinney, a friend of the Clutter daughter she who discovered the bodies, and to Alvin Dewey, the lead police investigator and also a Clutter family friend. If his celebrity doesn't work, Truman will grease the wheels by whatever means necessary. When the police eventually charge suspects, two young men named Dick Hickcock and Perry Smith, Truman uses those same tactics to gain access to them. Truman's fascination with the story makes him believe that he can revolutionize writing by expanding the germ of the article into what he calls a non-fiction novel. His personal involvement also changes as he grows emotionally attached to Perry, the seemingly sensitive and thus probable submissive in the criminal pairing, thus Truman becoming part of the story itself. Article or non-fiction novel, Truman knows that he has to take it to its natural conclusion, something which he cannot force. But also missing are the details of the November 14, 1959 event itself, something that neither Dick or Perry have divulged even in testimony.
In 1959, Truman Capote, a popular writer for The New Yorker, learns about the horrific and senseless murder of a family of four in Holcomb, Kansas. Inspired by the story material, Capote and his partner, Harper Lee, travel to the town to research for an article. However, as Capote digs deeper into the story, he is inspired to expand the project into what would be his greatest work, In Cold Blood. To that end, he arranges extensive interviews with the prisoners, especially with Perry Smith, a quiet and articulate man with a troubled history. As he works on his book, Capote feels some compassion for Perry which in part prompts him to help the prisoners to some degree. However, that feeling deeply conflicts with his need for closure for his book which only an execution can provide. That conflict and the mixed motives for both interviewer and subject make for a troubling experience that would produce an literary account that would redefine modern non-fiction.
On the night of 14 November 1959, in Holcomb, Kansas, a farmhouse is broken into by the criminals Perry Smith and Dick Hickock that expect to get US$ 10,000.00. With the policy of "no witness", the murderers kill the entire family. The homosexual writer Truman Capote travels to the small town with his friend Nelle Harper Lee and decide to use the topic to write a book. When the killers are arrested, he becomes friend of Perry for his own interest and then he falls in love for him, and gets a new lawyer for them, postponing their execution until 14 April 1965.
- Reading of the brutal murder of an entire family on a farm in Holcomb, Kansas, startles Truman Capote, a reporter for The New Yorker magazine, and he goes there to cover the story. What he finds is a murder without an identifiable motive, and, shortly thereafter, two men on death row for the murders who couldn't be more different. He befriends Perry, one of the two, and is befuddled to find an erudite, sensitive man, and Capote struggles to understand how such a man could be guilty of such crimes. Still, there is little doubt of Perry's guilt, for Dick, Perry's far less cultivated accomplice,has spoken of the murders in Capote's presence, though not admitting the murders were premeditated, and Perry makes no attempt to deny his participation.
Capote is so troubled and fascinated by the murders that he resolves to write a book about the incident. The problem is that the quality of his book will suffer unless he can learn what really happened on the night the crimes took place, as he would be unable to answer the very question that compelled him to devote so much time and effort to studying the murders.
Capote grows closer and closer to Perry, and their growing relationship and Capote's obsession with the successful completion of his project appear to motivate his attempt to intervene in the case and delay Perry's execution. In his prison visits to see Perry, he must delude him into believing that he is trying to get him a new trial and a fresh chance at acquittal. In truth, Capote's actions are self-serving, but the result is that he and Perry grow closer, and, eventually, Perry relates what really happened the night of the murders. An armed robbery went wrong, and the murders had been committed in the rage of the moment by Perry, who had been goaded by his accomplice, Dick, to kill all possible witnesses to their crime. Now in possession of the truth, Capote withdraws from the scene, perhaps understanding that the executions will now provide the final chapter of his book.
Not long after, Perry and Dick are executed, but Capote has already succeeded in understanding the Holcomb murders, and is ready to write a novel that will be celebrated as a masterpiece.