In Act 2, Scene 1 of Hamlet, what happens between Hamlet and Ophelia?

In Act II, Scene I, Polonius issues a complex, confusing set of instructions to a servant being sent to France to learn how Laertes is behaving. After the servant goes, Ophelia appears, upset and confused. She tells Polonius that Hamlet has visited her, dressed and behaving strangely. Polonius is convinced that Hamlet is behaving like a man in love. When Ophelia says she has done what Polonius instructed and rejected Hamlet's advances, Polonius concludes that Hamlet has been driven mad by that rejection and takes her to see Claudius.