This is a re-read via Audible, read by Grover Gardner.
Miles is on his honeymoon with Ekaterin while their two children are 'cooking' in a uterine replicator back home. They are diverted to Graf Station in Quaddie Space by Emperor Gregor, to sort out a diplomatic standoff between a rich merchant ship of Barrayarans and the quaddies, a gen-engineered race designed for nul-gravity. They have four arms instead of two arms and two legs. Miles reunites with Bel Thorne, Betan hermaphrodaite and former Dendarii mercenary, who is now in charge of running the station. After an attempt on his life, Miles discovers that one of the passengers on the Barrayaran ship has a thousand uterine replicators which are somehow tied into the Cetagandan gene bank. And there's the possibility of a Cetagandan super-plague.