The Human ambassador is having an affair with a Farsalian princess, who is a cousin of the Farsalian Matriarch. That leads to a riot, which leads to an incident, for which Suarez gets the blame, and then, oddly enough, the credit.
Because Stanislaus VII, Emperor of all Humankind, decides that he is bored, declaring war over the matter would be great fun and provide a break in the monotony of his opulent, indolent life. And that’s just to start with. Because desperate battles, secret missions, romantic entanglements, interstellar plots, and court intrigues all await Suarez and his doughty band in A Grand Imperial War.