When Miles Vorkosigan is disqualified from joining the Barrayaran Imperial Service Academy because he breaks both his fragile legs during the physical entrance test, he sets about trying to prove himself worthy by other means, especially since he blames himself for his aged paternal grandfather's death shortly afterward.

At Beta Colony, Miles comes across a tense standoff: "jump pilot" Arde Mayhew refuses to let anyone seize his obsolete starship, the only one he can fly, barricading himself inside and threatening to blow it up rather than let it be scrapped.

Miles defuses the situation by buying the freighter from the creditor, using ancestral family lands back on Barrayar as collateral (neglecting to inform the seller that the region is radioactive, a result of the former Cetagandan occupation).

To cover the credit note he used to buy the freighter, Miles masquerades as a mercenary leader (in transit) and takes a risky, but very well-paying job offered by Major Carle Daum: transporting a cargo into a war on Tau Verde IV to the losing side, Felice.

To save himself from the same charge, Miles suggests to Emperor of Barrayar (and foster brother) Gregor Vorbarra that he secretly accept the Dendarii as his own, to be employed whenever Barrayaran forces cannot be openly utilized.

Jo Walton, writing for Tor.com, described The Warrior's Apprentice as having "about ninety percent more depth than you’d expect it to have", but also notes that "the series does get a lot deeper and more complex as it goes on from here.