The Girl on the Forbidden Planet: Maisewith, Book 2

Maisewith faces certain death as she flees the cavern where she has lived for several years. She doesn't know how many, for there are no seasons, no stars or moons to mark her days, but long enough to mate, fall in love, and give birth to hybrid twins. Hybrid, because her mate is Laeperian, a human-like species covered in fur. She doesn't know how she will die, but any end she can think of is better than what awaits her if she is caught.
She endures a long tortuous trek though the many connecting caverns and passageways inside the mountain on the frozen moon, where she would die quickly if she made it to the surface. The larger part of her trek is in pitch darkness. When he falls off a cliff, she lands in a mine shaft and is rescued by intelligent creatures, who, though they look reptilian, are far more advanced technologically than the humans she descended from, Earthlings who invaded the planet Costra.
The Reptilian creatures take her to their home planet, Progcht, the coveted one her family wished to conquer. She learns the native language, but what use is that when she is imprisoned with others earthlings? In the open-air compound, enclosed by an invisible shield, she meets several people from Costra, including her former nanny and another adopted sister she didn't know she had. She also meets and befriends nine natives of the planet Jalspar, from whom the Laeperians descended.
When her nanny dies of a killer parasite, Maisewith escapes the prison compound to get help and convinces the natives to let her translate the spy bots the invaders brought with them. She and her captors learn that the parasite was purposely introduced in the hope it would spread to the natives. Biological warfare! They've got to find a way to stop the spread or die. Maisewith has to convince her captors to send her back to Costra to find the secret cure and to end the evil woman who abandoned her on the Ice Moon on her 18th birthday, the same woman he injected the parasite into her nanny.