If after this command thou fraught the court
With thy unworthiness, thou diest. Away!
Thou’rt poison to my blood.
So the theme here is forbidden love, it seems. Cymbeline, the king, has banished the curiously named Posthumus for the crime of being unsuitable for the king’s daughter. As the play opens Posthumus is lurking around again and proceeds to get himself re-banished. Following that, he makes a sizable bet with Iachimo regarding the virtues or lack thereof of his beloved. If Iachimo can corrupt her he wins the bet. If not he loses the bet and there will be some throwing down as well. Iachimo tries a mix of sweet talk and deception on Imogen but she’s not having any of it.