The rising action in Antigone is Antigone's decision to defy Creon's orders and bury her brother.
The rising action is the element of the plot which usually happens immediately after the exposition. It is the action by one or several characters which builds up suspense in the story. It is followed by all kinds of character decisions and plot circumstances which constitute the twists and incidents before the climax.
In Antigone, Antigone's decision to bury her brother creates tension between the characters because whereas she views it as a simple act of religious duty and respect towards her brother, Creon considers it an act of defiance against him.