Book 3 in the Virtual Reality series.
From the back of the book:
"Alone in the labyrinthine streets of the ancient city of Godorno, you frantically attempt to save your people - the Judian - from their tyrannical ruler, the Overlord. Terrified of being hunted down, the Judain have gone to ground. But now there is an even greater menace: Hate, the very embodiment of all that is sinister, has invaded the city. Its tentacles emerge form the sewers beneath the city, destroying everything. No one is safe. Will you be able to vanquish Hate and prevent the annihilation of your people?"