One of the new missions in the Fallout 4 April 2024 update is called All Hallow's Eve and centers on the Sole Survivor investigating a mysterious signal that has been tracked to the Harbormaster Hotel.

There is a section in this Fallout 4 mission where you have to figure out an access code to a door. You can't complete the quest without solving the puzzle, so we're going to break it down for you.

Once you defeat the ghouls in the Harbormaster Hotel after investigating the Halloween party setup, you’ll go through a hallway with five doors: two on the left, two on the right, and one at the end. The door at the end of the hallway is where you need to go, but there’s a keypad that requires a code to open it. Interact with the keypad and select “do nothing” to continue the quest. You’ll then be told to look for clues to figure out the password.

The game helps you out a bit with this; a marker will appear that will lead you to a nearby skeleton, with a note with a clue on it. The marker will only appear if you still have the All Hallows Eve quest selected on your Pip-Boy, so make sure you have it selected as it's a handy way to keep track of what you need to do next. The note, called "Lana's Note", offers some insight into how the code is solved.