A planet called "Prince Samual's World" had been bombed heavily during the Secession Wars and had spent about 400 years in isolation.

For years, Colonel Nathan "Iron" MacKinnie had been famous on the planet for his masterful defense of the city-state republic of Orleans against the expansionist kingdom of Haven (ruled by King David).

However, unknown to MacKinnie, the new Haven campaign was a lure to get Orleans' forces into the field, so that the Second Empire's more advanced weaponry (including spaceships) could destroy them.

Months later, drinking in a Haven tavern with his former top sergeant, Hal Stark, MacKinnie overheard a drunken Imperial officer boast of having been on Makassar, a nearby primitive planet that had a store of First Empire knowledge in a surviving building that locals treated as a temple.

Dougal thus offered MacKinnie an opportunity to go to Makassar disguised as a merchant/trader, to locate and return with information from the library to help Haven build a spaceship.

With Stark and a company of Haven agents not known to the Imperials, including Mary Graham, a young woman with a university education (highly unusual for Haven), MacKinnie boarded a ship of the Imperial Traders Association as the leader a merchant company looking for trade opportunities on Makassar.

He then maneuvered the most intelligent and suspicious of the high priests and Temple guards into a suicide mission, while his army defeated the barbarians by utilizing superior tactics.

One of MacKinnie's men was a physicist chosen for his eidetic memory, to research early plans for space travel.

The Navy officers insisted that MacKinnie and Graham, at least, be visibly punished, while the Imperial political representatives wanted to give Makassar a chance to continue to develop independently.

Makassar could not exploit the full ability of horses with its current technology: simple harnesses fastened around the neck.