Two of the first quests you will receive in "Divine Divinity" are finding cures for Verlat and Simon, patients of Goemoe and Otho in Aleroth. The Source, which Aleroth's healers use to heal, has been tainted, and there is only one healing gem left. Neither Otho nor Goemoe wants to use the gem because it means condemning the other patient to death. Your task is to find some way to use the healing gem on both patients.
Talk to Goemoe and Otho to receive the quests. Goemoe will be friendly, but Otho will reject the offer of help from a useless human like yourself.
Talk to the healing shrine, north of Goemoe's house, and get the last healing gem.
Enter the abandoned house in the far north of town. Among some packages (which you might have to move), you'll find a magic mirror, a book and a pair of leggings. The book will explain that the magic mirror can replicate gems.
Drop the mirror in the water to the south of Goemoe's house, and then drop the healing gem in. The mirror will duplicate the healing gem. Pick up both gems.
Return to Otho's house and give one of the healing gems to Verlat, located in a side room. You will gain 1,500 experience points and 1 reputation point.
Return to Goemoe's house and give the other healing gem to Simon to gain another 1,500 experience points and 1 reputation point.
Talk to Goemoe to gain a level of the Restoration spell.