Get this scenario at the Guild, and head for Mount Molor. Enter the house. There's plenty to look at in here - the stuff inside the wardrobe, the jewellery box on the table, and so on. The minimal path, however, is this: go through the door at the back, then through the middle door, and examine the picture on the wall; then back to the front room, and examine the box beside the stove twice; then back to the back room, through the right-hand door, and examine the alcove twice to open a tunnel into the depths of the mountain. This is a point of no return, so make sure you're kitted out and healed up before you go any further.
When you're ready, enter the tunnel. Head to the left and defeat the Shadow Dueller. Climb down the ladder and examine the sparkle for an Aqua Stone, then head north. If you have the Jump skill you can hop over to the sparkle on the left, which is a Chrome Staff. Keep going, enter the temple, and continue north. When you reach the door, you can choose either to burst in or hang back. If you choose to burst in, you'll meet Nealertos and fight a number of Demi-Ilyasters; if you wait, you can avoid the fight. Either way, you'll reach a save point, and if you take the passageway to the right down you'll reach an orb which will restore your HP.
You want this right-hand passageway anyway, but you want to enter it and go up the stairs. Head up and right, and Antoniana will appear and join your party. Now head back down past the HP orb and follow the passage round and up the other side. On the way you'll pass two tables with stone tablets on them. These have spells inscribed on them which increase your Agility and Defence, but it's unknown whether you can read them or not.
After you've defeated Vernon, enter the laboratory. When you regain control, head back south to the table with the knife on it and examine it twice to grab the knife. Take it back to Antoniana. Next you need to fetch Cycas (he's in bed in the room where you met Antoniana earlier). When that's done, head back to the save point.
This time take the door to the north. When the path splits, if you take the left door, you'll reach an orb which will restore your MP, HP or cure status depending on which stone near it you stepped on; when you've done that (if you needed to), follow the right path.
When you reenter the temple, what you need to do is take the middle passage and follow it round, then exit to the left, whereupon Antoniana will rejoin you. Head on in. You'll have to kill two Heat Gargs; that's no problem. The problem is that Antoniana won't be helping you in your next battle, which begins in a few seconds - against Nealertos.
This can be nasty if you're not careful. If your characters are weak, devote one of them to healing, and keep them away from him to spread the damage a bit. Nealertos is unpleasant, but not impossible; as usual he'll run out of MP before too long.
Try to pick up the book, then talk to Antoniana and leave the temple; return to the Guild for your reward.