This tragedy is concerned with Heracles' tragic end. For fifteen months the hero has been away from Trachis, where his family is staying. His wife, Dianeira, is worried and sends their eldest son, Hyllos, to find out where his father is. Meanwhile, the herald Lichas, arrives with a number of captive girls, to tell that Heracles will soon return as conqueror from Oechalia. However, Dianeira, learns from another messenger, that her husband has made, this war, merely to obtain king Egypros' young and beautiful daughter, Iole, who in now among the captives. When the unhappy woman hears this, as she wishes to keep Heracles for herself, she sends him by Lichas a new robe, which, in her innocence, she has dyed, with a love philtre at the advice, of the centaur Nessos. Meanwhile, something makes her suspect that the supposed philtre, is in fact lethal. Her suspicions are confirmed by the return of Hyllos, who, full of rage with his mother and grief for the fate of Heracles, reveals that the robe was fatal: it is devouring the hero's flesh. Dianeira enters silently into the palace and takes her own life. Soon Heracles is brought in, sunk in lethargy, in a pitiable condition. When he comes to himself, he asks Hyllos to bring him face to face with Dianeira to avenge himself. But he learns about the Centaur's philtre, and connects it with an ancient prophecy of Zeus of Dodona about his death, and knows that his end has come. He adjures his son to marry Iole, and gives him his final instructions for the preparation of his funeral pyre.