"Yeah, that would be the one. So, the original route was a straight shot to Barrayar from Earth, but these days Earth isn't nearly as much of a galactic hub as it was during the first wave of colonizations. Barrayar's new link to the wider galaxy goes through a planet called Komarr, which is so minimally terraformed that everyone has to live in sealed arcologies because there isn't enough oxygen outside to breathe, but they have a lot of wormhole routes so they get rich off trade and traffic. The Barrayar route looked to be more of the same. Except that one of Komarr's preexisting neighbours, the eight-planet Cetagandan Empire, decided they liked the look of this newly rediscovered planet whose inhabitants had only just figured out gunpowder again. They bribed the Komarrans to let them take an invasion fleet through, and conquered Barrayar fairly handily thanks to the technological disparity."