This scene begins with the entrance of two guards named Barnardo and Francisco at a change of watch. Both guards call out, in panic, to an unknown character. Soon after, they calm down and their superior Horatio and another sentinel Marcellus enter the scene. They inform him about the apparition, resembling their recently-dead King, that has been appearing during their watch.
Horatio doubts what they are telling him but he is quickly proven wrong when the ghost enters the scene. However the ghost ignores their attempts to speak to it and it quickly exits at the sound of the cocks crow.
For the rest of the scene the men talk about the death of the Norwegian Fortinbras, at the hands of Hamlet, and make speculations about how his son is planning to follow in his fathers footsteps and invade the land that Hamlet won. The sentinels decide it is wise to find Hamlet and inform him about the strange ghost.
React!