Hop down to the secret passage beneath the altar and follow the tunnel to a room with a hole in the floor. Break out the wall to the right, revealing lots of goodies. Return to the room with the hole and drop down to a room with a teleporter.

Approach the mural opposite the teleporter to open it. Go down the passage to the sewers and notice a 2-way fork. Go down the left hall and take the 1st left to find the entrance to the Underhalls. Enter.

Go forward down the hall and stairs. At the 3-way intersection, go right (to the left lies a trap), coming to a room with a dirty stream running through it and stairs leading down on the left. A barred drainage tube should be on the right.

Go down the stairs to the left and drop down into the stream. Follow it to a room with 4 tubes lining the walls. Climb the steps at the end of the room and turn the wheel on the wall (Raven ran out of buttons...). This will unbar one of the tubes (now the 2nd tube on the left). Enter it and fall down to another sewery room.

Turn the wheel on the left-hand wall to unbar the big drainage tube back in the room with the dirty stream. Go through the low arch on the left and follow the hall to a room with a lava pit. Climb up the spiral ramp that runs the circumference of the pit to the top.

Follow the hall to a wooden door. Open and enter a room with 3 imps and exits to 3 sides.

Take the hallway with the Tome of Power. When the hall dead ends, hit the wall to the left, revealing a secret passage. Go up the stairs and out into the hall. Turn left and follow the hall back to the room with the dirty stream.

Jump into the now unbarred drainage tube and follow it to a room with a ledge over each side and a handful of imps. Climb the stairs to the left and jump across to the opposite ledge to get the Prybar. Jump back across and follow the tunnel to the second entrance to The Dark Mage's Tower.

Come up through the grate and climb the spiral staircase, taking the (previously barred) 3rd door on the left. Go through and come to a great chasm with an imp statue.

Smash the planks on the left and find the alcove with the giant gear. Hit the gear to extend the bridge across the chasm. Hurry across the bridge before it retracts.

Go upstairs to the left and up the ramp. Go through the door and up another short ramp. Cross the room and go up one last short ramp to the Shadow Wizard's bedroom.

Notice the red dragon head mural on the wall. Break it out and take the Gold Sphere from its hiding place.