Basé sur la pièce de 1932, The Warrior’s Husband, By Jupiter n’était en fait qu’une énorme blague. Se déroulat dans la Grèce antique, les femmes sont des guerrières endurcies et leurs maris un peu sordides restent à la maison et cuisinent le souper. Mais dans les mains expertes des créateurs de musicals, le thème du renversement des sexes a donné lieu à une joyeuse aventure avec des chansons romantiques et comiques de Richard Rodgers et Lorenz Hart, un livret très émouvant (également de Rodgers et Hart) qui comprenait un correspondant de guerre nommé Homer…
Personne ne le savait à l’époque, mais By Jupiter serait malheureusement le dernier musical du duo Rodgers et Hart (l’année suivante, ils s'associeront encore pour un revival de leur succès de 1927 A Connecticut Yankee (), rajoutant quelques nouvelles chansons pour la production). Mais By Jupiter termina leur collaboration sur une note positive, et elle devint leur musical ayant eu le plus gros succès à la création avec 427 représentations (les productions originales de A Connecticut Yankee () et Pal Joey ()étaient finalistes avec 421 et 374 performances respectives).
Acte I
The Greeks are encamped near Pontus, where Hippolyta, Queen of the Amazon Warrior-Women, reigns. They have a ticklish assignment: as one of the Twelve Labours, Jupiter has ordered Hercules to acquire the sacred girdle of Diana from around Hippolyta's waist, and it looks like being quite a fight.
At the Palace, the women soldiers are squabbling, using the usual epithets, but with a feminine slant! Three Councillors discuss Palace politics; Pomposia needs Caustica and Heroica's support to promote her son at Court with a good prospect of marriage, but first has to explain what marriage is - a strange Greek system, at which the others laugh. When Hippolyta arrives, she leads the company in a celebration of their country. Pomposia presents her son Sapiens, who instantly takes Hippolyta's fancy and flirts wickedly with her: A heavy clinch is interrupted by a herald, who announces the landing of two foreigners. Hippolyta leaves to deal with this and when she returns, she is with her huntress sister Antiope and proudly introduces Sapiens to her, saying that one of them should marry him - then quickly hustles him offstage for herself! Antiope pretends not to mind.
Theseus and Homer, the foreigners, are announced. They are effusive to Hippolyta, and Theseus sings a number that Homer has written for him which develops into a huge swing dance routine. The men demand the girdle: Hippolyta refuses and throws them out, but Theseus manages to steal back to flirt with Antiope. Another out-of breath messenger announces that an army of Greeks - MEN! - is a week's march away: Hippolyta has to marry Sapiens to get from his ambitious mother the army equipment she needs, so a marriage is hastily arranged, delayed only by Sapiens fussing over his cape and veil! Hippolyta and the army then dash off to fight and Sapiens, like all wartime spouses, starts knitting furiously.
Acte II
In the Greek camp, we meet Hercules, who may be massive, but is a frightened wimp. Theseus broods on Antiope and in the Amazon camp, the sergeant broods on "The Boy I Left Behind Me". Sapiens arrives to claim his honeymoon, but even flirting and foot-stamping don't move Hippolyta. A Greek delegation enters, bringing a personal challenge from Hercules to Hippolyta; everyone drinks to the battle, Hippolyta trades girdles with Antiope so Hercules cannot grab the sacred one, and leaves. Sapiens shows Antiope how really to defeat a man - by kissing him - and she learns very quickly!
Theseus and Hercules arrive: Hercules is terrified by Antiope and takes refuge in Sapiens' tent, while Antiope and Theseus fight, until she defeats him in the special way she just learned and he happily carries her off, not knowing she is wearing the girdle! When Hippolyta returns and realises that the girdle is gone, Sapiens promises to lead the fight to get it back, as he knows how to deal with men .....
In the Greek camp, the girdle gets mislaid by Antiope in a big love scene with Theseus, and is found and tried by four nubile Greek camp-followers. When Sapiens meets them, his is electrified by their femininity and un-Amazon looks (not to speak of their behaviour). After a lot of horseplay, in which the girdle mysteriously disappears and Sapiens celebrates his new discoveries, it turns out that Antiope is off to Greece with Theseus, all the Greeks and Amazons are fraternising like anything, and Sapiens shows he has got - and is wearing - the girdle, which as King of the Amazons he presents to Hercules, though "You may have to have it let out a little!"