The insanely jealous Leontes has got it into his kingly head that his wife, Hermione, has been having an affair with King Polixenes. There's absolutely no evidence whatsoever that any such illicit dalliance has taken place, but Leontes is certain that it is and that Hermione is carrying not his, but Polixenes's, child.

Believing himself to be a cuckold, Leontes is hell-bent on wreaking a terrible revenge on Polixenes. To that end, he summons his chief counselor Camillo and orders him to have Polixenes poisoned. Not unreasonably, Camillo is more than a little disturbed by this insane command.

So instead of dashing off to carry out the dirty deed, Camillo tells Polixenes what Leontes has ordered him to do. Polixenes wants to confront the jealous king face to face and tell him that there's no truth to his suspicions. But Camillo wisely cautions him against such a course of action. It would be like trying to get the sea to obey the moon.

Camillo has a much better idea. He's going to arrange for Polixenes to slip away from Leontes's court. In return for his help, Polixenes promises Camillo asylum. And he'll need it, too, because if Leontes finds out about his escape plan, Camillo will almost certainly be put to death.