Here is a short plot summary of Cymbeline:
Cymbeline is the King of Britain. He marries an unpleasant woman who has an arrogant son called Cloten. Cymbeline arranges the marriage of his beautiful daughter, Imogen, to Cloten but she defies him and marries the poor but worthy Posthumus Leonatus.
Cymbeline banishes Posthumus, who goes to Rome. Before he goes Imogen gives him a diamond ring and he gives her a bracelet.
Several plot lines follow, involving disguises, mistaken identity, deceit, treachery and poison. The villain of the play is Iachimo, who bets a large sum of money against Postumus’ ring that he can seduce Imogen.
The play has a traditional comic ending. Iachimo confesses to his misdemeanours, the characters reveal themselves, all the misunderstandings are resolved and the lovers are reunited.