Freedom's Choice by Anne McCaffrey

Continuing the storyline from Freedom's Landing, this second book in the series finds the human and aliens on the penal planet Botany planning a rebellion against their slavemasters. After the Catteni subdue and transport to penal colony planets people from Earth and other civilizations for their Eosi masters, one Catteni, Zainal, chooses to remain on Botany. His plan? To join his fellow slaves in convincing the absentee owners of the planet to turn against the Eosi and free the colonists. McCaffrey is at her best with interspecies interactions and uniting for a goal against a common enemy. Highly recommended for sf collections.