Alas! poor Yorick. I knew him, Horatio; a fellow of infinite jest, of most excellent fancy; he hath borne me on his back a thousand times; and now, how abhorred in my imagination it is! my gorge rises at it.
Hamlet, thou art slain.
Many of the players converge upon a graveyard for the opening of this act, musing upon great concepts like life, death and whatnot while two clowns dig Ophelia's grave. Laertes and Hamlet are there and things get out of hand a bit, with them tangling in an empty grave.
Back at the castle Hamlet reveals to Horatio that there was a plot to do away with him (Hamlet). Shortly thereafter Hamlet and Laertes make nice but honor requires that they go ahead and duel anyway. They both end up dead, as do the king and queen - the latter is poisoned from a cup apparently meant for Hamlet. After this bloodbath is finished, word also comes that Rosencrantz and Guildenstern are also dead.
No happy ending here, friends. Move along.