Ultima IV: Quest of the Avatar/Dungeons Despise and Covetous

General hints
Mainland dungeons:
 * Dungeon Despise
 * Dungeon Destard
 * Dungeon Wrong
 * Dungeon Hythloth

Oversea dungeons:
 * Dungeon Deceit
 * Dungeon Shame
 * Dungeon Covetous

Enter the dungeons from their mainland entrance, go through the Altar Room and emerge from a different dungeon with oversea entrance. From there, either backtrack or use the Gate spell. Start from Dungeon Hythloth, because the White stone is required in all of the three Altar Rooms.

The Black stone

 * Talk to the dwellers in Magincia Ruins, and follow the trail.

Dungeon Hythloth

 * Get the lighter-than-air device and the White stone.

Dungeons Despise and Covetous

 * Get the Yellow and the Orange stones.

Dungeons Destard and Shame

 * Get the Red and the Purple stones.
 * Get Key Part from the Altar of Courage.

Dungeons Wrong and Deceit

 * Get the Green and the Blue stones.
 * Get the Key Part from the Altar of Love.
 * Get the Key Part from the Altar of Truth.