- The god Dionysus, son of Zeus, enters.
- He tells us that he's in disguise as a mortal.
- The god tells the audience about how he was struck from his mother, Semele, by a lightning bolt.
- He points out the remains of her house which still smolder and flicker with magic fire.
- This was all a trick of Hera's, who was jealous that her husband Zeus was having an affair with Semele.
- Dionysus praises his grandfather, Cadmus, who made a monument of the place his mother died.
- The god talks of how he's conquered places all over Asia, but Thebes is the first city in Greece where he's spread his wild rituals.
- He says that he's mad at the sisters of his mother, Semele. They spread a rumor around that he isn't really the son of Zeus, that his mother just slept around and after her death Cadmus made up the story.
- To pay Semele's sisters back for their insolence, Dionysus has incited them all to a frenzy. Currently, they're all dancing about in the mountains, and soon Dionysus will cause all the other women in Thebes to join them.
- Dionysus says that he's mad at Pentheus, the King of Thebes, who doesn't pay tribute to him as a god. The god tells the audience that he's going to teach the King and all of Thebes a lesson. If Thebes tries to resist, Dionysus will lead his followers in battle.
- Dionysus calls on the Chorus, female followers he's brought from Asia, to dance and sing around the city.
- The god goes off to the mountains to dance with the women of Thebes, now called the Maenads.
- As he makes his exit, the Chorus parades in.