The title of O. Henry's story is, indeed, suggestive; it provokes the reader to wonder about its significance, and it conjures the idea of death. However, as is characteristic of the inimitable O. Henry, the outcome of his story is still not predictable.
Known for following the local color of the turn-of-the century New York and the melodrama of Bret Harte with empathy for people and ironic reversals at the end, this author writes a curious and poignant narrative about two friends who live together in the art colony of Greenwich Village. On a floor below them dwells a little Jewish curmudgeon known as Old Behrmann, also a painter, who has curiously developed a fondness for one of the young women, who is called Johnsy.
Unfortunately for Johnsy, she has moved from California and has no resistance to the ills of New York's winter; consequently, the small woman contracts pneumonia.The old artist who has perennially been working on a "masterpiece," is greatly disturbed when Sue comes to him, describing Johnsy's despair at recovering. Sue tells Behrmann that Johnsy has decided that, like the ivy leaves that are falling off the vine outside her window, she, too, will give up and die when the last one falls off. In a burst of loving anger and frustration, Behrmann cries,
"Vass!...Is dere people in de world mit der foolisness to die because leafs dey drop off from a confounded vine? I haf not heard of such a thing....Ach, dot poor leetle Miss Yohnsy."
With Sue he goes upstairs to see Johnsy, but she is asleep, and only one ivy leaf is left. After Behrmann condescends to model for Sue, who paints a miner, he returns to his apartment. On the following day, Sue finds Johnsy staring at the drawn shade that covers the window and demands that Sue lift it. Reluctantly, Sue does so, but miraculously the one leaf has apparently survived the night's storm. This leaf inspires Johnsy to live after all.
When the doctor comes in the afternoon, he tells Sue that Johnsy stands a good case of recovery. Then, he informs her that he has another patient downstairs who has had an acute attack of pneumonia. It was he who painted on a window the last leaf that had really fallen. For Johnsy it was a life saver, but for Old Behrmann it was, indeed, the last leaf of life, painted in an act of heroism before he died that night.