Charlie Simms is a student at an exclusive New England prep school, Baird. Unlike most of his peers, Charlie was not born to a wealthy family and attends Baird on scholarship. To pay for a flight home to Oregon for Christmas, Charlie accepts a temporary job over Thanksgiving weekend looking after retired Army Ranger Lieutenant Colonel Frank Slade, who Charlie discovers to be a cantankerous blind alcoholic.
Charlie and George Willis, Jr., another student at the preparatory school, witness several students setting up a prank for the school's headmaster Trask. Following the prank, Trask presses Charlie and George to divulge the names of the perpetrators. Trask offers a bribe, a letter of recommendation that would virtually guarantee his acceptance to Harvard. Charlie continues to remain silent but appears conflicted.
Shortly after Charlie arrives, Slade unexpectedly whisks Charlie off on a trip to New York City. Slade reserves a room at the Waldorf-Astoria. During dinner at an upscale restaurant, Slade glibly states the goals of the trip, which involve enjoying luxurious accommodations in New York before committing suicide. Charlie is taken aback and does not know if Slade is serious.
They pay an uninvited visit to Slade's brother's home for Thanksgiving dinner. Slade is an unpleasant surprise for the family, as he deliberately provokes everyone and the night ends in acrimony. During this time the reason behind Slade's blindness is also revealed: while still an active officer, Slade used to juggle grenades while drunk. One grenade got away from him and exploded, causing his blindness.
As they return to New York, Charlie tells Slade about his complications at school. Slade advises Charlie to inform on his classmates and go to Harvard, warning him that George will probably be pressured into not maintaining silence, however, with his influential father (also an alum of Baird) behind him, his punishment will likely be light. Later at a restaurant, Slade is aware of Donna; a young woman waiting for her date. Although blind, Slade leads Donna in a spectacular tango ("Por una Cabeza") on the dance floor. That night, he hires a female escort. While Slade enjoys his evening with the escort, Charlie calls the ski resort that George and Harry (the student who planned the prank on Trask) are spending the break at and finds out from George that Trask has elevated his investigation of the prank and that George's father has become involved. The phone call makes Charlie more tense than ever.
Deeply despondent the next morning, Slade responds to Charlie's suggestion that they test drive a Ferrari. Charlie lets Slade drive the car and Slade begins speeding, attracting the attention of a police officer (Ron Eldard), whom Slade manages to appease without giving away his blindness.
When they return to the hotel, Slade sends Charlie out on a list of errands. Charlie initially leaves the room but quickly becomes suspicious. Charlie returns to find Slade in his military uniform, preparing to commit suicide with a gun from which Charlie had made Slade promise to remove the bullets earlier, regarding which Slade states "I lied". Charlie intervenes and attempts to grab Slade's gun. Slade, however, easily overpowers him, threatening to shoot Charlie before himself. They enter a tense argument, with both struggling for the gun; however, after Charlie bravely calms Slade, he backs down.
The two return to Baird. Slade gives Charlie the money he owes him in cash and then touches Charlie's face, feeling for the first time how Charlie looks. He also offers Charlie any references he many need in the future and has Manny drive him home.
At school, Charlie and George are subjected to a formal inquiry in front of the student body and the student/faculty disciplinary committee. As headmaster Trask is opening the proceedings, Slade unexpectedly returns to the school, joining Charlie on the auditorium stage for support. For his defense, George has enlisted the help of his wealthy father, and divulges the names of the perpetrators, qualifying that his vision wasn't clear. When pressed for more details, George passes the burden to Charlie. Although struggling with his decision, Charlie gives no information, so Trask recommends Charlie's expulsion.
At this, Slade cannot contain his silence any longer and launches into a passionate speech defending Charlie and questioning the integrity of a system that rewards informing on classmates. He tells them that Charlie has shown integrity in his actions and for the committee to not expel him because this is what great leaders are made of and he will make them proud in the future. The disciplinary committee decides to place on probation the students named by George, and to give George neither recognition nor commendation for his testimony. They excuse Charlie from any punishment and allow him to have no further say in the inquiries, to loud applause from the student body.
As Charlie escorts Slade to his limo, a female political science teacher, Christine Downes, who was part of the disciplinary committee approaches Slade, commending him for his speech. Seeing a spark between them, Charlie tells Ms. Downes that Slade served on President Lyndon Johnson's staff. A romantic prospect is hinted between Slade and Ms. Downes as they part ways.
Charlie takes Slade home, where they go their separate ways. The colonel walks towards his house and greets his niece's young children happily as Charlie watches by the limo.