This is one of the oddest, kinkiest YA SF books I've read in a while. In her other fantasy novels, Hoffman has often touched upon the theme of people with too much power over others and how they abuse that power. Teenaged Kaslin has been at the whim of his parents, a bully, and now the aliens he found in a cave on the human-colonized planet where he lives. His relationship with the bully becomes disturbingly romantic (though it mirrors the plight of many female characters in romance novels) and the aliens get pretty freaky too. It's a short book, I finished it on a lazy afternoon.