You'll enter a room with a huge dog in an enclosure (Fluffy), so ignore it and carry on to the next room to find...Draco Malfoy! Anyway, that double-crossing creep has got you in a trap, and curses you with the Body-Bind Spell (Locomotor mortis!) to leave you to be discovered by Snape. Luckily, he hasn't learnt it very well, for as soon as he leaves you can move.
1. Immediately go upwards and cast Alohomora on a mirror in the room. Then go through to another dark room. Don't expect Snape to come cruising if you take too long, but don't take your time.
2. Go up and left until you find a clay pot blocking a switch. Smash the pot and enable the switch with two straight Flipendo blasts.
3. Double over to the large pit, where a moving bridge has been enabled. Step onto it and let it carry you to the other side.
4. If you must, open the chest on the left side to get a Chocolate Frog.
5. Proceed right and upwards to find your way to a dead end with a pressure plate and a bridge. The bridge leads to nowhere until you step on the plate and turn the bridge around! But you step on the plate, and heeerrrress SNAPE!
6. He comes dashing up towards the place you are, so quickly hide behind a vase or at least stay out of his view. He'll mutter a threat and walk off. When he's gone across the bridge, immediately double back to it and cross the bridge and follow Snape, being careful not to get too close, until you reach a corridor with nooks.
7. When he stops patrolling the corridor, hide in a nook until he passes, then slip into an area blocked by a chasm and a Flipendo block. Move the block over the chasm and smash the clay pot in the way.
8. Carry on, moving another block and crossing another chasm...WAIT! Here comes Snape again! Wait until he stalks back into the corridor, then proceed to a two-way path. Take the left one.
9. You'll reach a place full of clay pots. Move the Flipendo block close to the rightmost pot, smash the pot in your way, then move another Flipendo block which has magically appeared just slightly ahead (don't worry if it clears the way for Snape).
10. Now double back and cross the now-clear corridor, hiding in nooks when Snape passes.
11. You should now see three locked doors. Open the middle one to see one of the blocks you can't reach, then double back and open the left door.
12. See that Flipendo block? Now you're on the correct side, move it. Double back to the middle room and you will see another block which intercepts you. So double back, unlock the right door and enter.
13. Remembering it's position, walk to the appropriate position and fire off a well-aimed Flipendo jinx. Now double back to the middle door - the way is clear. Escape!
"You escaped the trophy room! Wait 'til Ron and Hermione hear about this!"
You end up on...
Remember the secret bookcase Ron told you about? Now's the time to USE IT! So make your way, dodging more prefects. In case you forgot, it's on the left side of the stairs leading to Floor 5. Go up, and yippee! Back to the Common Room!
In the Common Room, Ron marvels at your bravery, while Hermione gives you a jolly good berating for misusing her well-taught Alohomora. She leaves, and comes back in the morning to scold you again before flouncing off yet again. Then Ron tells you that you have Herbology in Greenhouse 1 in the Grounds. So use the secret bookcase way (remember where you emerged from on Floor 7 after taking that way!) to Floor 4, and make your way down to the grounds.