Hunting party - Elizabeth Moon

Heris Serrano was an officer born of a long line of officers, and a life serving in the ranks of the Regular Space Service was all she had ever known and all she ever wanted - until a treacherous superior officer forced her to resign her commission. This was not just the end of a career path; it was the end of everything that gave her life meaning.
But even ex-Fleet captains have to eat, and Heris finds employment as 'Captain' of an interstellar luxury yacht, working for the eccentric Lady Cecelia de Marktos. Being a rich old lady's chauffeur isn't quite the same as captaining a Fleet cruiser, but nothing Heris will ever do again will compare with that. Or so she thinks . . .
For all is not as it seems aboard the Sweet Delight. The smuggling ring is only the start of it. For on a visit to a seemingly innocuous pleasure planet, Heris stumbles across a very sinister hunting club and finds herself fighting for her life - and for the lives of friends she thought she'd never see again.