The novel begins with 16-year-old Steve Harmon writing in his diary awaiting for his trial for murder. Musing on his short time in prison so far, he decides to record this upcoming experience in the form of a movie screenplay. Kathy O'Brien, Steve's lawyer, informs him on what will happen during the trial. At this stage, only two of the four accused – James King and Steve – will be tried, since the other two accused – Richard "Bobo" Evans and Osvaldo Cruz – have entered into a plea bargain. When the trial first begins, Steve flashes back to a movie he saw in his school's film club and the discussion he had with his teacher in which they discuss the idea of predictability.
The trial begins with the opening statements of the prosecutor Sandra Petrocelli, Miss O’ Brien, and King's lawyer, Asa Briggs. Petrocelli labels the four accused men, including Steve, as "monsters." The lawyers call on several witnesses, including Salvatore Zinzi and Wendell Bolden, illicit cigarette traders, who admit to buying cigarettes that came from a drugstore robbery that led to the murder. The story of the trial is often broken up by a variety of flashbacks, including ones showing that King is only acquainted with Steve, that King had accused Steve of pulling the trigger during the robbery. Petrocelli calls as a witness Osvaldo Cruz, who is affiliated with the Diablos, a violent street gang. Cruz admits to participating in the crime only due to coercion by Bobo.
Steve recounts a visit from his father, who wishes Steve would have gone on to attend his alma mater, Morehouse College. After recounting various news reports covering the robbery and murder, Steve documents his arrest and his mother's panicked reaction. Before returning to the trial, Steve writes in his notes that he cannot psychologically handle writing down the tragic details of the robbery itself. The coroner, the city clerk, and a detective are questioned in a four-way split screen montage. Miss O'Brien warns Steve not to write down in his notebook anything he wants the prosecutor to see.
According to Cruz, the original plan was that Steve would go into the drugstore and signal if the coast was clear. After King and Bobo robbed the store owner, Mr. Nesbitt, Cruz would slow down any potential pursuers. All sources indicate that Mr. Nesbitt drew a gun, which one of the robbers wrestled him for, causing the gun to discharge and kill Mr. Nesbitt. Bobo takes the witness stand to say that James King pulled the trigger and vaguely recalls that Steve, whom he hardly knows, was meant to give an all-clear signal.
Briggs argues that neither King nor Steve was ever involved in the crime since the only eyewitness to the robbery saw only two men involved, which can be accounted for by Bobo and Cruz alone. Though Miss O'Brien seems doubtful of Steve's innocence, she wisely has him distance himself from King. Steve appears to know King and Cruz only as remote acquaintances, and Bobo hardly at all. Steve testifies that he does not particularly remember where he was on the day of the robbery, but that he certainly was not a participant. The defense systematically casts the honesty of Petrocelli's witnesses in doubt. Although many of the testimonies contradict, even the most incriminating toward Steve claims only that he acted as a lookout in the first stage of the robbery.
George Sawicki, Steve's film club mentor, serves as a character witness, proudly defending Steve's moral character. Briggs, Miss O'Brien, and Petrocelli finally make their closing statements, before the jury decides on a verdict. James King is found guilty, while Steve is found not guilty. As Steve moves to hug O'Brien, she turns away, leaving Steve to question why. The end of the novel takes place five months after Steve has been cleared of all charges and released from prison. Steve has continued his film-making, but his father has moved away, creating a noticeable distance between the two. He is still confused as to Miss O'Brien's demeanor at the end of the trial, wondering whether she saw some real Steve or a "monster."