The Manifold, an aggressively expansionist shadhavar Empire that threatens your confederation of mostly-democratic states in the Upper Reaches, are doing magical experiments on captured unicorns. The confederation's scouts have located a forward operating base where unicorns captured by the Manifold are all being processed; most of them are then relocated to new lands in the Manifold's home islands and settled as subjects, but some of them never make it out. The Confederal Defense Force will make a daring raid on the facility in an attempt to rescue the prisoners; your party is charged with gathering intelligence and identifying any equipment of exceptional value that should be captured, as there is no hope of holding the base against the Manifold's reinforcements.
General setting information here, part of the larger PRPG continuity albeit largely unconnected to the events of the main campaigns.
This session is an indirect sequel to The One Where the Party Abducted a Crystallomancer.