SARAH:  Act 1 ended with the ghost’s great revelation that Hamlet’s father was poisoned by Claudius. The ghost demanded revenge, and Hamlet appeared to be re-invigorated by this command.

RALPH:  Without worrying too much about whether the ghost is truly the apparition of his dead father, he seems intent on carrying out the ghost’s command — but perhaps not right away. Until Hamlet has the means and opportunity to strike at his more powerful adversary, King Claudius, he’ll put on an "antic disposition", that is, he’ll pretend to be crazy.

SARAH:  About the same time, Hamlet’s relationship with Ophelia has taken a turn for the worse. Her father, Polonius, fearing that the young prince Hamlet is not serious about his daughter, has forbidden her to continue seeing him. Some time has passed between the end of Act I and the start of Act II — perhaps a number of weeks. Since then, Hamlet apparently has had no contact with Ophelia — until just before this scene.

RALPH:  The scene starts with Polonius giving some instructions to a servant, who will be going to France to check up on Laertes.  Just as they’re wrapping up their business.  Ophelia comes in, clearly distressed, and she tells her father about an unexpected visit from Hamlet.