my cousin vinny

Plot

While driving through the fictional Beechum County, Alabama, Billy Gambini (Ralph Macchio) and his friend Stan Rothenstein (Mitchell Whitfield) accidentally neglect to pay for a can of tuna fish after stopping at the 'Sac-o-Suds' convenience store. After they leave the store, the clerk is shot and killed. Billy and Stan are then pulled over and detained in connection with the murder. They are taken to the fictional town of Wazoo. However, Billy and Stan assume they were detained for shoplifting, so they behave guiltily and manage to indirectly implicate themselves in the shooting. Due to circumstantial evidence and a series of miscommunications, Billy ends up being charged with murder, and Stan is charged as an accessory to the crime. The pair call Billy's mother, who tells her son that there is an attorney in the family, who would be willing to take the case. Unfortunately, Billy's cousin Vincent LaGuardia Gambini (Joe Pesci), better known as Vinny, is a neophyte personal injury lawyer from Brooklyn, New York, newly admitted to the bar (after six attempts and six years) and has no trial experience.

Although Vinny manages to fool the trial judge, Chamberlain Haller (Fred Gwynne) about being experienced enough to take the case, his actual ignorance of basic court procedures gets him into trouble immediately, much to his clients' consternation. For example, after appearing before the judge at the arraignment in a leather jacket and without a tie, Vinny is thrown into jail for contempt of court after failing to enter a plea and behaving disrespectfully toward the judge. On his second appearance in court, Vinny does not even bother to cross-examine any witnesses in the probable cause hearing. To make things worse, the three eyewitnesses turn out to be stupid, incompetent, or liars, who swear that they saw Billy and Stan at the crime scene. Sheriff Dean Farley also testifies that Billy confessed, but Billy had merely been incredulous at the suggestion that he was suspected in a murder when he said, "I shot the clerk?!" As these claims go unquestioned, it appears that the prosecution has an airtight case that will inevitably lead to a conviction at the trial. Meanwhile, Vinny's inability to get a good night's sleep at the poor accommodations he finds, coupled with his own stubborn and proud refusal to accept the help of his fiancée, Mona Lisa Vito (Marisa Tomei), further impairs his performance.

After Vinny's poor showing at the hearing, Billy and Stan decide to fire Vinny and use the public defender, John Gibbons (Austin Pendleton). Vinny asks his cousin for one more chance to prove himself in court, and Billy reluctantly agrees. The trial then opens with Vinny representing Billy and the public defender representing Stan. Vinny manages to again draw the ire of the judge by showing up late and wearing a gaudy second-hand suit (because his new suit accidentally fell in the mud). After again being cited for contempt, Vinny sleeps through the prosecutor's opening statement. With nothing prepared and no idea what the jury has already heard, Vinny makes a brief statement: "Everything that guy just said is bullshit. Thank you." The DA, Jim Trotter III (Lane Smith) objects on the ground that Vinny's entire statement is argumentative. Judge Haller sustains the objection and strikes everything but "thank you" from the record. However, it turns out that Stan's attorney suffers from a serious case of stage fright and delivers an inept, stuttering opening statement. He again missteps when cross-examining Sam Tipton (Maury Chaykin), the first prosecution witness. Stan's attorney asks questions that Tipton easily answers, which serves to strengthen the case against Billy and Stan. Vinny at last manages to do something right, as he asks a devastating series of questions on cooking grits that discredit Tipton's prior testimony while presenting an alternate theory of the crime: that two other men, driving a similar car, committed the murder after Billy and Stan had left the scene. After Tipton admits that what he saw was consistent with Vinny's theory and that he "may have been mistaken" in what he said during the direct examination, Stan dismisses the public defender and declares that he wants Vinny to represent him. In addition, Vinny finally gets some much needed sleep when he decides not to be bailed out and stays overnight at the prison.

As the trial goes on, Vinny continues to expose the weaknesses in the district attorney's case. The second witness, Ernie Crane (Raynor Scheine), swears he recognized the defendants and their car even though he was looking through several obstacles. After calling attention to the "rusty, dusty, dirty" screen on Crane's window and the large amount of foliage in the middle of his view of the convenience store, Vinny gets the witness to acknowledge that he may have merely noticed "two guys in a green convertible," consistent with Vinny's theory that the crime was perpetrated by two similar-looking men in a similar car. The third witness, Constance Riley (Paulene Myers), has severely impaired vision yet still swears that she recognized the defendants as the murderers. However, after Vinny shows that she can't see well enough to tell how many fingers he is holding up across the courtroom, half the distance from her house to the crimescene, she admits that she wasn't able to see well enough to positively identify the defendants.

However, Trotter has one more surprise witness, FBI analyst George Wilbur (James Rebhorn), who testifies that his analysis of the tire marks left at the crimescene shows that they are identical to the tires on Billy's car. With only a brief recess to prepare his cross-examination and unable to come up with a particularly strong line of questions, Vinny becomes frustrated and lashes out at Lisa by taunting her about the usefulness of her wide-angle photographs of the tire tracks. A hurt and angry Lisa leaves him to work alone. But finally, in the courtroom, Vinny looks at the photos again and realizes that they hold the key to the case: Billy's car could not have produced the flat and even marks because of the technology used to make its suspension. Vinny, however, needs Lisa to testify to this, and she has been avoiding him since he lashed out at her. Vinny finds Lisa outside the courtroom and forces her inside, where she triumphantly confirms Vinny's theory that the car at the crime scene was definitely not Billy's 1964 Buick Skylark, but a 1963 Pontiac Tempest, the only car resembling the former and able to produce the marks at the crimescene. Vinny then calls Wilbur again, who confirms that it would be impossible for Billy's car to have made the marks at the crimescene. Sheriff Farley then testifies that two men resembling Billy and Stan were arrested in Georgia for possession of a stolen Pontiac Tempest and a .357 Magnum revolver, the same caliber bullet that was used to murder the victim in this case. Trotter then drops all the charges against Billy and Stan.