In the Iceman Cometh, regulars at a Greenwich village bar await the return of Theodore "Hickey" Hickman, a salesman who always throws a party when he arrives. But, this time, Hickey has found salvation and is completely sober. The play examines the futility of pursuing the American Dream. Each of the patrons in the bar have given up on their dreams or somehow betrayed themselves, including Hickey, who reveals that he has killed his wife and ends up turning himself in.
The Iceman Cometh is set in Harry Hope's downmarket Greenwich Village saloon and rooming house in 1912. The patrons, twelve men and three female prostitutes, are all dead-end alcoholics who spend every possible moment seeking oblivion in each other's company and trying to con or wheedle free drinks from Harry and the bartenders. They drift without purpose from day to day, coming fully to life only during the semi-annual visits of the salesman Theodore Hickman, known to them as Hickey. When Hickey finishes a tour of his business territory, which is apparently a wide expanse of the East Coast, he typically turns up at the saloon and starts the party. As the play opens, the regulars are expecting Hickey to arrive in time for Harry's birthday party. The first act introduces the various characters and shows their bickering among themselves, showing just how drunk and delusional they are, all the while awaiting Hickey.
Joe Mott insists that he will soon re-open his casino. Cecil "The Captain" Lewis and Piet "The General" Wetjoen, who fought each other during the Boer War, are now good friends, and both insist that they'll soon return to their nations of origin. Harry Hope has not left the bar since his wife Bess's death 20 years ago. He promises that he'll walk around the block on his birthday, which is the next day. Pat McGloin says he is hoping to be reinstated into the police force, but is waiting for the right moment.
Ed Mosher prides himself on his ability to give incorrect change, but he kept too much of his illegitimate profits to himself and was fired; he says he will get his job back someday. Hugo Kalmar is drunk and passed out for a majority of the play; when he is conscious, he pesters the other patrons to buy him a drink. Chuck Morello says that he will marry Cora tomorrow. Don Parritt is a former anarchist who shows up later in the play to talk to Larry about his mother (Larry's ex-girlfriend) and her apprehension due to her involvement in the anarchist movement.
Finally Hickey arrives, and his behavior throws the other characters into turmoil. He insists, with as much charisma as ever, that he sees life clearly now as never before because he is sober. Hickey wants the characters to cast away their delusions and embrace the hopelessness of their fates. He takes on this task with a near-maniacal fervor. How he goes about his mission, how the other characters respond, and their efforts to find out what has wrought this change in Hickey take over four hours to resolve.
During and after Harry's birthday party, most seem to have been somewhat affected by Hickey's ramblings. Larry pretends to be unaffected but, when Don reveals he was the informant responsible for the arrest of his own mother (Larry's former girlfriend), Larry rages at him; Willie decides McGloin's appeal will be his first case, and Rocky admits he is a pimp.
Eventually, they all return and are jolted by a sudden revelation. Hickey, who had earlier told the other characters first that his wife had died and then that she was murdered, admits that he is the one who actually killed her. The police arrive, apparently called by Hickey himself, and Hickey justifies the murder in a dramatic monologue, saying that he did it out of love for her.
Hickey's father was a preacher in the backwoods of Indiana. Evidently he was both charismatic and persuasive, and it was his inheriting these traits which led Hickey to become a salesman. An angry kid trapped in a small town, Hickey had no use for anyone but his sweetheart, Evelyn. Evelyn's family forbade her to associate with Hickey, but she ignored them. After Hickey left to become a salesman, he promised he would marry Evelyn as soon as he was able. He became a successful salesman, then sent for her and the two were very happy until Hickey got tired of his wife's always forgiving him for his whore-mongering and began to feel guilty. He next recounts how he murdered her, supposedly to free her from the pain of his constant philandering. But in retelling the murder, he laughs and tells Evelyn, "well, you know what you can do with that pipe dream now, don't you?" In realizing he said this, Hickey breaks down completely. He realizes that he went truly insane and that people need their empty dreams to keep existing. The others agree and decide to testify for insanity during Hickey's trial despite Hickey's begging them to let him get the death sentence.
The others all return to their empty promises and pipe dreams except for Parritt, who runs to his room and jumps off the fire escape, unable to live with the knowledge of what he has done to his mother after discarding of the last of the lies about what he did and his motivation. However, despite directly witnessing the young man's fatal leap, Larry's eyes continue to remain closed to the reality of his situation ("by God, there's no hope! I'll never be a success...Life is too much for me!") and he is left sitting, claiming to long for a death that Parritt embraced before his very eyes while insisting it is he, Larry, who is the only one of the group to take death seriously. In spite of Parritt's having actually taken the suicidal initiative, Larry grimly maintains his pose and thereby lives.