Before the play begins . . .
In Thebes, Zeus takes a fancy to Cadmus’ daughter Semele, and she becomes pregnant. Semele, duped by Zeus’ wife, asks to see him in his divine form, and dies in the heat of his blazing glory. Zeus rescues the unborn Dionysus and sews him into his thigh until it’s time for the youngest of the Olympian gods to be born. As a new god, he must seek followers, and he starts in the east before returning to his Greek hometown of Thebes.
As the play begins . . .
Dionysus (also known as Bacchus) tells us where he’s been and that the Thebans are refusing to worship him as a god. He has, therefore, caused all the women to take to the mountains to celebrate him among nature, and he’s got plans for the men who remain. He’s dressed himself as a human being and leads a group of Bacchants from the east, whom we meet in their long introductory song.
The old men Teiresias and Cadmus come out getting dressed up in Dionysian garb. They’ve decided that if you can’t beat him, you might as well join him, and, besides, joining the god of wine might be fun. Theban ruler Pentheus, however, is adamant about keeping the exotic god away, and is suspicious that the women on the mountain are indulging in indecent activities. Teiresias and Cadmus try to convince Pentheus to respond to the god moderately, but they don’t succeed.
Dionysus, disguised as a Stranger, has been caught by Pentheus’ guards, and Pentheus cross-examines the god before imprisoning him. Dionysus escapes, of course, making it seem as if the palace is crumbling and ablaze. A Herdsman arrives to tell us about the women on the mountain, including Pentheus’ mother Agave: they’re living an idyllic life in tune with nature until they begin ravaging the local livestock in a bloodthirsty rampage.
Pentheus prepares to take arms again the women, until Dionysus convinces him he would learn more going in disguise as another female follower of the god. Pentheus, intrigued, agrees to be dressed as a woman and heads off to the mountain.
No sooner does a messenger tell us the horrible result of that journey—Agave, mistaking her son for a mountain lion, rips him limb-from-limb with her bare hands—than Agave herself appears holding in triumph the head of Pentheus. Cadmus finally makes his daughter see what she has done under the influence of Dionysus, and Dionysus reveals himself as a god and tells the Thebans of his wrath and their fate.