In act V scene 1, Hamlet is at the graveyard where they are burying Ophelia and he picks up a skull and reflects on what life will be like in the future.
In act V scene 2, Hamlet is having a sword fight with Laertes while Gertrude and Claudius watch on. Gertrude takes a sip of the wine and is poisoned by it. The King dies from a sword wound that was poisoned and Laertes dies the same way. Laertes struck hamlet with his sword and poisoned him and dies.
The overall theme of Hamlet is revenge and death. Both of these play key points through out the play. Hamlet is trying to get revenge on Claudius for killing his father, but he got killed in the process. Hamlet knew that one day everyone would turn to bones and be nothingness.