The Game Beyond — Melissa Scott

A star-flung empire the prize -- in a deadly war of successionThe Silvertree Empress is dead, the last of her line. The heir named in her will is an impossibility, her favorite, Keira Renault, member of a family deposed and disgraced generations before -- the man she claimed as the power behind her throne. As the Empire's notables jockey for position behind the various claimants, Keira must defeat his rivals in simulation and reality -- and somehow hold the factions together long enough for the Empire to survive.