The Lightless Kingdom The Unbalanced Earth #2 Jonathan Wylie 1989
After restoring the magical balance of the rocking stone, Gemma begins her search for the remarkable valley that she has saved and longs to be re-united with Arden.
During their travels together, she had been shown the different futures which could exist for her world, and must now decide how to use her unreliable wizardry for the best.
She knows that the Guild in Great Newport must be overthrown, and cannot bear to consider the alternative. But other, unforeseen forces are at play on the southern continent and what is the Lightless Kingdom?