O’ Henry’s (William Sydney Porter) stories share a typical trait almost every time. That is the unexpected turn towards the end of the story. And this peculiar quality of his stories has made the author popular among readers.

Throughout the story, Johnsy had been lying with high fever which had left her mind morbid and full of strange fancies. She thought that there was a relationship between the falling vine leaves from the wall outside the window and her life-span. The strange thought caught her mind that she would die as soon as the last leaf fell. And the doctor felt that it was difficult to cure her unless she wants to live by herself. And arousing that hope and will was not easy for her friend Sue who tried many ways to do so. Until it was towards the end of the story when only one leaf was left, the chances looked really bleak.

In the morning when the last leaf was still there against the wall, Johnsy started to show some good signs to recover. She wanted to eat and wished to paint the Bay of Naples some day. She said —

Something has made that last leaf stay there to show me how wicked I was. It is a sin to want to die.

Though the readers should feel good at this, it rather looks unreal and strange. Moreover the readers get puzzled on what the story conveys after all.

But the real story begins when the doctor talks about Behrman catching a Pneumonia, and more so in the very last stanza when Sue comes to Joanna and reveals Behrman’s death and how he had got the cold by painting that last leaf in the windy and rainy night.

…look out the window, dear, at the last ivy leaf on the wall. Didn’t you wonder why it never fluttered or moved when the wind blew? Ah, darling, it’s Behrman’s masterpiece – he painted it there the night that the last leaf fell.

It seems like till the last stanza it was the setup going on for the story to begin and the main story starts after that. To realize it well, eliminate that closing stanza and the story would look like half-done without a message or even without much sense. As the last leaf saved Johnsy’s life, the last line seems to have saved the entire story.