Nightmares are dreams too.
Ulthia is a bioship, carrying forty different biomes filled with creatures and plants who reside in those domes. It carries on it two sentient races. The Uppers who keep the technology functioning and live in the metal encased levels around the engines and base of the ship. And the Myans who reside in the biodomes, are an ever-adapting race, and who live to serve the Uppers and the biological functions of the ship.
The ship appeared in Sol's celestial space ten years ago. In exchange for the ability to follow Earth's orbit and collect solar power, the aliens offer terraforming technology to save the ravaged planet's biosphere, vacations to Ulthia through a lottery system, and, rumour has it, space travel technology.
During a ten-year celebration, Samantha Wilde's name is drawn to go to Ulthia. She has no friends or family, and so goes alone.
But even for that, Ulthia is prepared. Assigning her an Adventure Buddy, a Myan assigned to her based on her social profile to best suit her travel needs and desires, the keepers of Ulthia make certain Sam will have the time of her life.
Xin is like any Myan male. Looking to please, adapt, and provide. He and his Adventure Buddy companions were all chosen for their accelerated adaption abilities. Like all Myans, he has sworn his life to service and finds solace in submitting to the whims of another.
It's the vacation of a lifetime, a dream come true.