Heracles opens with Deianeira bemoaning her lot as an unloved and routinely abandoned wife. While Heracles is off completing his labors and winning fame and glory, Deianeira sits at home and thinks about her other suitor, the river-god Achelous. Would her life have been different if she had swallowed her repulsion at the chimerical wooer, constantly changing shape between a bull, a serpent with shiny coils, and a man with the face of an ox...at least he would be a more constant presence. Instead, while Deianeira's praying that she might die rather than have to face a marriage bed with Achelous, along comes the glorious son of Zeus and Alcmena and challenges the dreaded Achelous for her hand.
What a moment! One second you're thinking "crap...looks like I'm going to marry a water serpent." And the next second along comes the exemplar hero, all rugged and immortal. Yet, for Deianeira, married life did not go as she had planned.
"Since I have been joined to Heracles as his chosen bride fear after fear has haunted me on his account; one night brings trouble, and the next night in turn, drives it out. And then children were born to us, whom he has only seen as the farmer sees his distant field, which he visits at seedtime and once again at harvest. Such was the life that kept him journeying to and fro, in the service of a certain master."
Deianeira is referring,of course, to Eruystheus, who spent twelve years coming up with twelve virtually impossible tasks for Heracles to perform; these tasks being ordained by the priestess of Apollo and when completed would obtain for Heracles immortality. So, Heracles has a lot on his plate and parenting isn't really a priority. And while he runs around, becoming a legend, Deianeira is left to parent, alone and isolated.
"For Deianeira, as I hear, hath ever an aching heart; she, the battle prize of old, is now like some bird lorn of its mate; she can never lull her yearning nor stay her tears; haunted by a sleepless fear for her absent lord, she pines on her anxious, widowed couch, miserable in her foreboding of mischance."
What Deianeira does not know is that Hera has had it out for Heracles from the beginning. Classic Zeus, had to run around and get beautiful, but mortal Alcmena knocked up. Hera, obviously annoyed by Zeus' constant, exhaustive infidelities decides she will destroy Heracles and she eventually smites him with temporary madness, during which he kills his wife Megara and his three children.
After Heracles wins the hand of Deianeira, they head back to Tiryns and on their way must cross the river Evenus; at the rivers edge they happen upon the centaur Nessus, who offers to carry Deianeira upon his back. Midway across the river, Nessus gets a little frisky and Deianeira shrieks; Heracles immediately turns and shoots a feathered arrow that had been dipped in the poison of Hydra. In his last breaths the centaur tells Deianeira to gather some of his blood as a potion that would be efficacious in preventing Heracles from loving another woman. Thinking nothing of it and obviously not remembering the ancient proverb: "The gifts of enemies are no gifts and bring no good," Deianeira keeps the potion hidden for the unfortunate day when she may have need of it.
Now, completing his last labor, Heracles has made a pact that if he has not returned in fifteen months he would either be dead or return to uninterrupted peace. The fifteen months are up and Deianeira is anxious and worried not knowing what to expect.
As she ruminates about her luckless, neglected heart, a messenger approaches telling her that none other than Heracles is on his way home! And he is sending along a war bride, princess Iole...this does not bode well for Deianeira. The years have been unkind to her and here, before her, is a fair maiden that Heracles declared war for when he was unable to woo her into being his paramour. Now after conquering her country and killing her father, she has been dragged back to Tiryns to wait for the return of Heracles alongside Deianeira.
Deianeira, distraught, remembers the secret potion, and after quickly dousing one of Heracles' cloaks liberally with the stuff, sends it away with the messenger saying it is a token of her love for Heracles and a gift for his joyous return. Feeling nervous about the potency of the secret concoction, Deianeira oscillates between feeling joy that Heracles is finally, unalterably hers...and a growing unease and foreboding. She cautions the choir "do not act with zeal if you act without light" and waits for her husband to return.
Meanwhile, Heracles, after being given Deianeira's gift he is slowly being suffocated/flayed to death by the poisonous cloak. His only thought is revenge and with each agonizing step he demands that Deianeira be brought to him so that he can embrace her and she too can taste the agony she has wrought. But after hearing that her suspicions were confirmed and that she has essentially murdered her husband, Deianeira kills herself, unable to cope with the misery she has inflicted.
"So I do not know, unlucky me, where to turn my thoughts; I only see that I have done a fearful deed. Why or wherefore should the monster, in his death-throes, have shown good will to me, on whose account he was dying? Impossible! No, he was cajoling me, in order to slay the man who had smitten him; and I know this too late, when it is of no help."
Like Ajax, impaling himself on the sword of his enemy, Heracles is killed by an enemy of the past, and as he realizes that his death is in accordance with a prophecy, he quickly insists that he be carried up a hill and burned on a pyre. His last demand that his son, Hyllus, marry Iole, his lover and ignorant accomplice to his death. Hyllus complies, only because she is insanely beautiful. As the mortal part of Heracles is burned away, he gains immortality, ascending to Oylmpus, there to be reconciled with Hera and to marry her daughter, the slender-ankled Hebe.
As the play ends, Hyllus chants to the chorus: "No man forsees the future; but the present is fraught with mourning for us, and with shame for the powers above, and verily with anguish beyond compare for him who endures this doom. Maidens, come ye also, nor linger at the house; ye who have lately seen a dread death, with sorrows manifold and strange. In all there is naught but Zeus."