A work of literature can be diagrammed in terms of five elements: exposition, rising action, climax, falling action, and resolution.

The story hinges on being told from Della's point of view. Through her, and particularly her worries about money for a Christmas gift for Jim, we learn how poor the young couple is. This is the exposition (background) that drives the plot. Della has saved and saved but doesn't have anywhere close to enough to buy a nice gift for her beloved husband.

The rising action is her attempt to remedy this problem. She does this by selling her hair, which is quite beautiful and falls to her knees. She is very proud of and attached to her hair. The audience feels what a wrench it must be when she tells the insensitive hairdresser to cut if off so that she can raise the money for Jim's gift.

The climax hinges on irony and comes when the couple realizes that each has sold their most beloved possession to buy a gift for the other that the other now cannot use: Della has sold her hair for a watch chain for Jim, and Jim has sold his watch for a costly brush and comb set for Della. We are as surprised as Della when we learn Jim has sold his watch, because we have only seen the action through Della's eyes.

The falling action is in the acceptance and love the husband and wife each feel for the other. Neither is angry: they both understand the love that drove the other person's action.

The resolution comes as the narrator leaves the reader with the moral that love is the greatest of all gifts, noting that in their love, this young, seemingly foolish couple was as wise as the first magi who brought gifts to the infant Jesus.

A plot diagram is a common teaching tool that illustrates the main chunks of a piece of literature.  There are typically 5 main chunks.  The exposition/introduction, rising action, climax, falling action, and resolution/conclusion.  

The exposition of "The Gift of the Magi" is the introduction of Jim and Della.  In addition to their names, the exposition also tells the reader that Della and Jim are married and really poor.  The exposition also includes setting details.  It's nearly Christmas, and the story begins in their apartment. 

The rising action of the piece is Della trying desperately to figure out a way to buy Jim a nice Christmas present.  The only thing that she can think of is to sell her hair.  She sells her hair, gets $20 for it, and rushes from store to store trying to find the perfect gift.  

Oh, and the next two hours seemed to fly. She was going from one shop to another, to find a gift for Jim.

The climax of the story is when Jim arrives home and sees Della and her newly cut hair.  

The falling action of the story is the gift exchange between Della and Jim.  They both realize that in order to buy a present for each other, they each had to sell what was most precious to them.  On top of that, the gifts that they purchased for each other are meant to go with the item that the other person has now sold.  

The conclusion of the story is Jim and Della sitting down together for dinner.  That doesn't sound like much, but it's important, because neither Jim nor Della are angry at each other.  They both know what it took to buy the gift, and the thought is far more important to them than the actual gifts.  Included in the conclusion is O. Henry's narration about who the Biblical magi were.

 But let me speak a last word to the wise of these days: Of all who give gifts, these two were the most wise. Of all who give and receive gifts, such as they are the most wise. Everywhere they are the wise ones. They are the magi. 

 

The plot diagram of a story is a tool that is commonly used to organize a story into certain segments. It also gives the framework for analyzing and understanding written prose. The plot diagram in "The Gift of the Magi" is a simple yet powerful one. 

Exposition: Jim and Della want to buy gifts for each other, but neither one has the money to do this. They are a young couple who don't have extra money for gifts. They love each other very much and want to buy a gift for one another.

Rising Action: Della gets her hair cut off to get the money to buy a chain for Jim's watch. Jim sells his watch to buy hair combs for Della's beautiful hair. 

Climax: Jim finds out Della cut her hair and can't use the combs, and Della finds out Jim sold his watch and can't use the chain for his watch. The two get rid of the very thing the other bought a gift for. The love they have for each other outweighs them getting rid of the material things.

Resolution: Jim and Della find out that it doesn't matter if they get each other gifts, just because they don't have the money. Them not being able to buy the gifts doesn't mean that they don't love one another. 

This is a wonderful story about love and sacrifice. The love Jim and Della have for each other is the best gift of all.

Exposition:  The opening scenes where Della is counting her money and realizing that she is short.  Also, when O. Henry describes the shabbiness of their apartment.  This lets us know two crucial things--that Della really loves her husband, and, that they are both very poor.

Rising action:  Della realizes that she doesn't have enough money introduces a bit of conflict into the story--what will she do?  More rising action occurs when she takes her hair down and gets an idea, then leaves the apartment.

Further rising action:  after her locks are cut, she impatiently awaits Jim's return home--what will he think?

Climax:  Jim returns, discovers her shorn hair, and the gift that she purchased.

Falling action:  He shows her that he sold his watch, and got her hair combs.

Resolution/Denouement:  The commentary from O. Henry about the magi, and the intent of their precious gifts, and tying that to the young couple.

I hope that helped--good luck!