The story takes place in 1959 at Welton School in Vermont in the USA, an upper private preparatory school for boys who want to get into famous universities : the Ivy League. The fall term begins with a very traditional ceremony during which a new English Literature teacher, Mr. John Keating, former student at the institution, is introduced.
With his unconventional teaching methods, he inspires the students to act as individuals. He encourages them to think for themselves. They have to find new points of view, to discover their own ways and feelings, and to "Seize the day." But Mr. Keating's classes call the attention of the other teachers of the school and of the Principal : Mr. Nolan.
The film focuses on the new teacher and on a group of his students : Neil Perry, Knox Overstreet, Charlie Dalton, Steven Meeks, Richard Cameron and Gerard Pitts, who have known each other for several years, and a new one, Todd Anderson. Once, in a few lessons, the whole new perspective on life is taught, they start to follow their own ideas. In many ways, there are against the conservative policies of the institution or with their parents' expectations.
After the first class, they get out again the School Annuary of the studious years of Mr. Keating in Welton. There, he is said to be a member of the "Dead Poets' Society." When asked, he says that it was a kind of literary club that held secret meetings in a cave. They decide to revive it and to convene their own version of the "DPS". So they gather in the cave at night to read verse aloud in a state of newly inflamed passion and share their creative efforts. Neil, for his part, takes part in a play, although his father advised him against it, and Knox, as for him, will do whatever he has to in order to conquer the girl he has fallen in love with. Todd overcomes his shyness and throws his parents' present out from the bridge.
The conflicts arises when, one night, Charlie, who has changed his name to "Nuwanda", brings two girls to the meeting. He tells his friends he published a very daring article in the school magazine, signed by the "Dead Poets' Society", asking for the acceptance of girls at Welton. The institution punishes him severely but he does not reveal the names of the members of the group. Mr. Keating is warned by Mr. Nolan to drop his unorthodox teaching methods.
Neil's performance day arrives. The play is a real success, but his father gives him the surprise of his presence. Although Neil confronts him, he is unable to tell him about his ambitions and finally commits suicide at home. His parents ask the school to investigate the case and the boys are intimidated to accuse Mr. Keating of being a bad influence on them and of causing Neil's death. Mr. Keating's ardent belief that words and ideas can change the world turns out to be true when the tragedy rocks the school and when the conservative play-it-by-the-book administration makes him a scapegoat. The teacher is forced to leave the school but his best students now become rebels with a cause. They show their loyalty to him and to what he has taught them and changed for them.

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