Sam is on her own, but her distance from the Doctor doesn’t make for a trouble-free life. Rescued from an out-of-control spaceship, she finds herself on a tiny moon which is the only known source of dreamstone, a mysterious crystalline substance that can preserve your dreams — or give you nightmares. Pitched into the middle of a conflict between the mining company extracting dreamstone and ecological protesters, Sam thinks it’s easy to decide who the good guys are — until people start dying, and the killers seem to be the same species as some of her new friends.