Summary of Act 1
Act 1 scene 1 was primarily about the ghost visiting the castle. Even though the ghost comes, he just stands still and doesn't say anything before vanishing. Also, this is not the first time the ghost has appeared, he has come twice before. Everyone is quite positive that the ghost is the late King Hamlet of Denmark.
Act 1 scene 2 on the other hand is about the King's coronation. They also hold the funeral of his father's death. Soon after the funeral, he announces that he is getting married. Everyone is skeptical about him getting married this close to his father's funeral. He says he is doing this to balance the mourning of the funeral with the excitement of the wedding. The King also sends Cornelius and Voltimand to Norway to give Fortinbra's Uncle a letter basically saying "Tell your nephew to stop threatening Denmark." Also, Hamlet asks to attend his old school in Wittenberg but he is told no. At the end of the scene, Marcellus and Horatio swore they saw the dead King dressed in full armor, so they decided to tell Hamlet.
In act 1 scene 3, Laertes gives advice to Ophelia about Hamlet. He feels that Hamlet isn't a good option for Ophelia to be dating, even though Ophelia is in love with him. Laertes thinks that Hamlet is just going to use Ophelia until he finds someone better to date. Usually, class levels don't mix and since Hamlet is royalty and Ophelia isn't, their relationship most likely wouldn't work out in the end.
During act 1 scene 4, Hamlet, Horatio, and Marcellus all meet at the battlement in the castle. While waiting for the Ghost to come, they look through the windows and see a drunk Claudius, Hamlet is disgusted. When the Ghost finally comes, Hamlet is curious as to if the Ghost is friendly or if he is evil. The Ghost then asks Hamlet to come with him to tell him why he is here. Marcellus and Horatio try to get Hamlet to stay with them, but he goes anyways.
The last scene, the Ghost tells Hamlet that he is his father's spirit. He said that Claudius poisoned him and Hamlet needs to seek revenge. The Ghost says that Claudius has Corrupted Denmark and Gertrude. The ghost then leaves as the sun goes down. When Hamlet and Marcellus come back into the room, they see that Hamlet is shaken up and they ask what happened. Hamlet refuses to tell them because he doesn't want them knowing what the ghost said.