Explore the Mansion
Car
Hurry, you need to get out of here as soon as possible! Open the door on the left, then Move out!
Outside Mansion
Whew, that was a close one! This mansion is the only place around, surely your sister must have gone inside. But the door's locked, so we need to figure out how to follow her. While we're stuck, might as well commit a federal offense.
Open up the mailbox to find the Envelope. Open the Envelope to find the Letter and the Pendant. Examine the Letter to learn that one of the Master's students, Dracan, fell to dark influences and became some sort of evil wizard. Whoever wrote the Letter mentions that the enclosed Pendant can stave off the undead. Sounds fancy, so go ahead and Take the Pendant.
Upon putting that into your inventory, there's an ominous flash of lightning and the front door mysteriously unlocks itself. Since there seems to be a storm moving in, we might as well find shelter. Move through the magically opened door.
Foyer
A comfy little room, if not strangely oppressive. The couch looks like it would be nice to sit in, but upon Examination, you find something hard sewn into the lining. Plus the fireplace isn't lit, so there's nothing to stave off the cold. No sense sticking around then, go ahead and Open the door on the right and Move through.
Library
A stately library, replete with many fine books. The only thing to do here is to Open and Examine the Mag.Book on the table. This will teach you the Cloudisi, Stillini, Thundede, and Telemaze spells. Once these are added to your spell book, head back to the Foyer
Foyer
Open and Move through the other door in the room.
Hallway 1F
Before doing anything, pay close attention to the layout of this room. The Move Map shows five exits, one on the top of the map and two on each side. Looking at the doors, you'll see that the one in the back right is open. This means that you're actually standing in the back of the hallway right next to the stairs.
If you try to Open any of the doors, a ghost will appear in the middle of the hallway with her back turned toward the camera. Since we know where we're actually standing, we know that we can safely make our way to the staircase. That's the best option you have, unless you prefer being killed by a ghost.
Hallway 2F
We've got five exits in here and a wall fish. You don't need to enter all of these rooms, and for the purposes of this walkthrough we'll skip the unnecessary bits. You can explore on your own, but I'm going to call out the optional paths in case you want to see them for yourself.
Optional
Open the door on the upper right and Move through.
Guest Bedroom
The only thing to do in here is to Open up the bureau. Inside there's a Ruby you can take if you really want to. Once it's in your possession, though, you'll be cursed. You'll be slowly killed as long as you have the Ruby in your pockets. You can Leave this in an outside area to save yourself.
We're going to start the main path by Opening and Moving through the middle door on the right.
Spiral Stairway
Take the Axe sitting conspicuously on the floor.
Optional
Move up the staircase, and you'll find yourself outside of a Jail Cell of some sort. If you Open the door, and ghost appears and warns you that there's no escape. You should probably listen to him, but if you feel adventurous, you can always Move into the cell…
Head back out into the hall.
Hallway 2F
Open the door in the bottom right and Move through.
Closet
A small closet full of all kinds of fun stuff to purloin. Most of it you don't need. Take the No Ghost and the Spray (labeled Spider Cider). If you're an ambitious little inventory-filler, you can also Take the Hatbox (and the Hat inside it), Dirtybox, Soapbox, Ashtray, Bowl, Pesticde, and the Mop. When you're done in here, head back into the hall.
Optional at this time
Hallway 2F
Open and move through the door on the bottom left.
Master Bedroom
Take the Diary 2 from the small table. Open it to read some fun lore. It looks like the servant who wrote that letter from the mailbox was on to Dracan's evil was before the Master was and stole his star…whatever that is. Most have been a powerful token, as its theft seems to have helped in sealing him away. Apparently it's been stored in a hingeless box for safekeeping. And there's a key hidden in a place known only by a chair…hmmm, cryptic.
You can also Take the Bottle 1 and the Candle 2 if you want to. Nothing else to do in here, so Open the door on the left and Move through.
Master Bathroom
The Voodoo Doll (aka Doll) hanging on the wall, the Towel 3, Mask, Bottle 3, and Bottle 4 are all superfluous but you can Take them if your mighty need for inventory is too great to ignore. When you're done with this side jaunt, head back to the hall.
Hallway 2F
Open up the door in the upper left and Move through.
Scary Bedroom
There's a small table by the bed with the Diary 1 and the Candle 1, but neither of them serve any real purpose. The real goal here is to Open the table by the bed. Inside is the Scroll 1, Open this to learn the DollDoll spell.
Optional
Open the door to enter the Scary Bathroom. Nothing to do in here right now, but if your thirst for inventory cannot otherwise be slaked there's a few things in here you can Take. The Towel 1 and Soap are out in plain view, and you can Open the hamper for the Towel 2.
Once you've learned the spell, head back downstairs to the Hallway 1F.
Hallway 1F
We're back here with the ghost bride, but this time we came armed. Open the No Ghost, and then Use it on Scarlet to vanquish her. And now we can explore the rest of the first floor.
Optional
Open the lower right door and Move through.
Parlor
There's not much to do in this quaint little parlor. But there is a door just begging to be opened. Go ahead and Open it, then Move onto the porch.
Veranda
A spider! It's okay, it kept moving across the railing…that was a close one though. While we're out here, Use the Spray on the railing. Move back to the Parlor, and then come right back out onto the Veranda. The Spider will scuttle across the railing again, but then get stuck in the Spider Cider and be paralyzed. Might as well Take it. Head back out to the hallway.
Open the upper left door and Move through.
Dining Room
Take the Bouquet sitting on the table. You can also take the Bowl, but it doesn't serve any purpose. Open the door at the back of the room and Move through.
Study
That door is locked, and can't be opened at this time. The desk, however, is ripe for the Open command. Take the Card inside the drawer. You may think a periodic table cheat sheet would be useless, but you would be very wrong. Go back to the dining room.
Dining Room
This time take the door in the upper left.
Kitchen
There are a bunch of items here that you can Take, most of which you don't need. You will need to Take the Knife 2. If your pockets are feeling too empty for comfort, you can also Take the Fry Pan, Pot 1, Pot 2, Knife 1, Jar 1, Jar 2. When you're done looting the room, Move to the right.
Pantry
Take the Matches on the third shelf up. There's nothing else useful in here, but if your pants feel empty you can Take the Plate, Dish, Flourbag, Spatula, Salt Jar, Salami, and the Thermo. Head back out into the Kitchen.
Optional
Kitchen
Move to the left.
Servant's Quarters
A very tidy room! If you Examine the painting, you'll notice some marks on the wall as though the painting has been routinely moved. Using it makes no difference, not does a good old fashioned Hit. If you Examine other objects in this room, you discover that the lamp does not appear to be plugged into anything. Wonder if that still works…
One way to find out! Time to Use the lamp! With an audible "click," the lamp switch causes the painting to slide to the side, revealing a hidden book. But, wait, there's now a ghost in your way! He's threatening you to leave him and his precious alone. Tempting, but we really want to read that book, so instead of leaving him alone, Use the Spider on him. Luckily, he was an arachnophobe in life and flees at the site of the paralyzed Spider.
With him gone, Take the Diary 3. When you Open it, you get the Servant's side of him taking Dracan's Star from him. There's another clue about the box it's hidden in: "It never opens, it has no locks. Dracan's Star never discerns. In fire it freezes. In ice it burns." You can also take the Brush and the Cologne in here. Head back out to the Kitchen.
Kitchen
Make your way back to the Foyer.
Foyer
Use the Knife 2 on the couch. Take the Key 1 that is revealed. This key opens up a few different things, and we're going to start with the Master Bedroom, previously listed as an optional path. If you need a reminder, or skipped it, Move back to the Hallway 2F and then through the lower left door.
Master Bedroom
You can loot this place if you haven't already, but the important action will be to Use the Key 1 on the cabinet. Once you have it opened, you'll want to Take the Box. The Scroll 2 and Scroll 3 contain some useful hints, so I would recommend at least Opening them up to read them. You can Take the Bottle 2 if you really want to…just don't drink it. Once you have the Box, head back to the Foyer.
Foyer
Use the Matches on the fireplace to get a mighty blaze started. Use the Box on the fireplace, which will reveal Dracan's Star. Go ahead and Take the Star. Now Move back into the hall.
Hallway 1F
Open and Move through the bottom left door.
Game Room
When you first enter this room, a little demon will dance it's way across the screen. You'll notice a key in its mouth, but there's nothing you can do about this right now.
Use the newly-acquired Key 1 on the Cabinet to unlock it. Take the Gyp.Doll hiding inside of it. Speak or Use the DollDoll spell to get the Gyp.Doll to come to life and give you a hint. "Talk to my pious brother. He can help you find your sister. A word from him can open doors in high places." As a bonus, you also learn the O Sesame spell.
Take note of the plate on the floor. There's also a fun easter egg if you Use the gramophone. It'll badly play the Shadowgate theme before breaking down. That's all you can do in here for now, to Move through the top door.
Trophy Room
Nothing you can do with the stuffed animals. You can, however, Take the Cage sitting on the floor. Move through the other door in here.