is determined to bury him because it is decreed by a law higher than the decree of Creon---the "laws of the gods." She sees that her efforts may lead to death but it will be a death with "honor" (Sophocles 414-415). All of these statements establish that Antigone is basing her decision (which she has clearly already made though not yet carried out) on a higher moral standard than that established by civic law. She knows the price she will likely pay for her decision and the act which implements that decision, and she is willing to pay that price. She knows well what she must do for her dead brother, and nothing--not the law, not her own sister's pleadings, not death itself--will deter her from doing it.
Because at the very beginning of the play the decision has clearly already been made by Antigone to bury her brother, the rest of the play is meant to establish the ethical standard by which that decision has been made, to contrast her decision with the contrasting stands of the vengeful Creon and the fearful Ismene, and to follow the implementation of that decision by Antigone and the consequences of that act.
With respect to Ismene, Antigone's bravery only emphasizes the cowardice of her sister. Antigone is determined to do what is right for her brother in accordance with the desires of the gods, while Ismene wants to cause no trouble for herself or anyone else, and is willing to obey the orders of Creon even if it means that their brother will lie unburied in disgrace. Although Ismene does have a change of heart later in the play, it is Antigone and Antigone alone who makes the moral decision and follows it through to the end, through exile and death.
In announcing his decision to prevent the burial of Polyneices, Creon declares that his primary principle is his dedication to doing whatever he needs to do to ensure the survival of the State. However, it is clear from the hateful and vengeful nature of his words that he is...