In Britain, two noblemen discuss recent events at King Cymbeline's court. We learn that his daughter, Imogen, was betrothed to Cloten, the son of Cymbeline's new Queen. However, the princess secretly married Posthumus, an Italian-born orphan who was raised as a ward of the king. Infuriated by the young people's disobedience, Cymbeline banished Posthumus and imprisoned Imogen--an action made even more tragic considering that she is his only child: his two sons, Guiderius and Arviragus, were kidnapped years ago.
The Queen meets with Posthumus and Imogen, and she promises to be kind to them, not "evil-eyed" as most stepmothers would be in such circumstances. She swears that she will work to convince Cymbeline to relent and then allows them to take one last walk together around the garden before Posthumus goes into exile. When she has gone, Imogen declares that she sees through the Queen, whose kindness is all an act. The two lovers then agree to be faithful to one another, and they exchange love-tokens--a ring and a bracelet--and promise to wear them forever. As they speak, however, Cymbeline enters with his court, and Posthumus departs in haste. The king begins berating his daughter for her conduct, and while she defends herself vigorously, he orders her locked away, despite the Queen's protests. Pisanio, Posthumus's servant, comes in then, bringing word that as his master departed he was assaulted by Cloten; however, the two men were separated before anyone was hurt. He now offers his services to Imogen, saying that Posthumus wished him to serve the Princess during his exile.
Outside, Cloten boasts to two gentlemen of the court about how he would have cut Posthumus to pieces had they been allowed to fight. The lords flatter him to his face, but their conversation with each other makes it clear that the Queen's son is a strutting fool and a poor swordsman who would have had no chance against Posthumus. Meanwhile, Pisanio tells Imogen of how much Posthumus will miss her, and he promises that they will hear from him soon. Then, Imogen goes to attend to the Queen.
The scene now shifts to Italy, where Posthumus has gone as an exile. In the home of his friend Philario, he debates with a large company of men from around Europe on the respective virtue of their countries' women. One of the company, Iachimo, declares that there is no woman born who cannot be seduced. Posthumus angrily disagrees and declares that his Imogen is invulnerable--that she would never betray him with another man. Iachimo says that he will take this as a challenge and go to England to attempt the seduction, and he convinces Posthumus to make a bet with him: If Imogen succumbs to Iachimo, Posthumus will give him his ring; if Imogen chastely refuses, Iachimo will pay Posthumus 10,000 ducats.
The early scenes in Britain serve primarily to introduce the major characters and the predicament of Imogen and Posthumus. Shakespeare returns to an oft-used device of having the main characters and their plight introduced by observers: in this case, two gentlemen of the court, who quickly lay the groundwork for the play's two plots strands, the one involving Posthumus and Imogen, the other dealing with the king's missing sons. One of the structural weaknesses in Cymbeline lies in the fact that the latter plot, once introduced, languishes until Act III, when the playwright finally takes it up again--this is a sharp contrast to other Shakespeare plays, notably King Lear, in which dual plots enjoy graceful integration from the beginning.
The early scenes, then, focus entirely on Imogen and Posthumus, who appear as a rather generic pair of lovers, at least for now. Their exchange of tokens and professions of fidelity are significant, if trite, since they lay the groundwork for Iachimo's deception later on. During these scenes, we also briefly meet Cymbeline, the Queen, and Cloten. King Cymbeline, although the title character, remains an opaque and uninteresting figure throughout the play, blustering at his daughter and seemingly completely subservient to his wife, who quickly shows herself to be exactly what she denies being--the stereotypical evil stepmother. Cloten (pronounced, appropriately enough, "Clot-ten") proves himself a boorish fool from the beginning; later on, we will wonder what Imogen sees in the lackluster Posthumus, but if Cloten is the alternative, then her choice is understandable.