Sentences wording and phrase choice

Are these sentences clear and worded in the correct way? Also, which phrase to begin the last sentence should I use?
Flint and his friends soon left Thorbardin and traveled to the city of Tarsis to see if they could commission ships to transport the refugees away from the war. However, upon reaching the city, the group discovered it to be landlocked and under the tacit control of the dragonarmies. (Shortly afterward/A short time later), the companions were separated during an attack on Tarsis by the Red Dragonarmy and a contingent of blue dragons.