"LEGO Harry Potter" is an action adventure game for the Nintendo DS. Players use the stylus to control Harry and cast spells. In the third year, there is a chapter called "Pursuing Peter Pettigrew," in which you must follow Peter Pettigrew on the Marauder's Map. You begin this chapter in the halls of Hogwarts. Once the chapter is complete, you will fight against Pettigrew in the Shrieking Shack.
Head right into the next room and avoid being seen by the Prefect.
Cast the transfiguration spell by drawing a sideways "S" with the stylus on the stone statue to turn it into a staircase.
Go up the staircase to collect the key and head back outside of the room. Head left down the hall and unlock the door with the key. Continue heading left through the door and cast the wingardium leviosa spell to lift the object out of the way. Hit the switch underneath the object to reveal a secret room to go into.
Defeat the Bogarts in the room using the patronus spell. The Bogarts will drop an object you need to place on the pillar in order to open the next door. The next door will need a password to open, so search around for clues.
Cast wingardium leviosa on the object to the right of the door to reveal a painting, which will give you the first clue. Cast the transform spell on the second object to reveal another painting. Hit the bookshelf on the far right with a reducto spell to find the last clue. Head back to the door to open it.
Head left and defeat the Bogarts guarding the painting. Carry the painting to the shiny spot on the wall, which will open the nearby door. Speak with the next painting to receive a clue and then defeat the three ghouls guarding a chest. Open the chest to find the key to open the door near the painting.
Head to the right and avoid the Prefect, cast reducto to remove the objects blocking the door and enter the next section.
Cast lumos by tapping on your character with the stylus and drawing a "U" symbol to light your path. Head left and then up the path. You will find three statues; repair the first, cast descendo on the second and cast transform on the third. One statue, you will see, is missing its head.
Find the head of the statue by heading down and left. The head should be sitting on the ground near the first pathway. Head back to the statues and place the head in its proper place, opening another door.
Tap the painting in the next area to find another clue. Cast reparo or wingardium leviosa to find the remaining pictures to give you more clues. Once you find all the clues, a parseltongue object will appear.
Tap the object and blow into the microphone of the DS to speak in parseltongue. A secret passage will open to go through.
Cast lumos to see in this new area and head left and then up towards Peter Pettigrew. The level will end once you have spoken to Peter.