Antigone tells Ismene that she plans to bury her brother Polynices. She is acting against Creon's decree, which is that no one is allowed to bury or mourn Polynices or else they will be punished by public stoning.
Someone has buried Polynices and acted against Creon's decree. We know that it was Antigone who buried Polynices but Creon and the Guard still don't know who it was.
Antigone gets captured by the Guard and sent to Creon. She does not deny that it was she who buried Polynices, against Creon's decree.
Creon and Haemon are arguing about Creon's decision to execute Antigone. Haemon does not agree with Creon.
Antigone is walking to the cavern that is devoid of human life. The cavern was picked by Creon so that Antigone could be placed in there with little food. She says that nobody will mourn her because she has no friends.
Tiresias goes to Creon to tell him that the gods are not accepting their offerings. Tiresias tells Creon that he must give Polynices a proper burial and release Antigone from the cave or else Creon will be punished by the gods.