The rising action in The Gift of the Magi would be the part of the story that leads to both Jim and Delia purchasing the special Christmas gifts for each other.
"Jim has suffered a thirty-percent pay cut, and the two must scrimp for everything. On the day before Christmas, Delia counts the money she has painstakingly saved for months. She is dismayed to find she has less than two dollars, hardly enough to buy anything at all. After a good long cry, Delia determines to find a way to buy Jim the present he deserves. As she looks into a mirror, an idea comes to her."
The rising action occurs before the climax of the story which occurs when they give each other the gifts.