 Before the play begins, Hamlet's uncle, Claudius, has murdered his father, has taken over the throne of Denmark, and Hamlet is suspicious of this, but he doesn't have any proof, and he's worried because, of course, he could be wrong. Early in the play, the ghost of Hamlet's father appears. The ghost is very solemn in telling him what's happened, gives him all the details of the murder, how he was out in the garden, and how his uncle came and poured a poison in his ears.