Star Gods: Book Four of Seeds of a Fallen Empire
by Anne Spackman
In Star Gods, the action returns to an alien home world, where the alien Alessia is raised. Her mentor, Hinev, creates the immortality serum and tests it on his pupil, Alessia, who becomes one of her planet's intergalactic explorers. The explorers eventually visit the Earth of the ancient past on their long journey in space.