A young man named Roy Mercer leaves home to take up duties as a wireless operator aboard a newly built merchant ship, moving from his wartime experience with the Camp Brady Wireless Patrol into a peacetime maritime career. The narrative traces his entry into shipboard life, learning the instruments and customs of the service, and voyages between northern and southern ports. Episodes ashore and afloat explore the practical use of wireless skill to thwart sabotage, handle emergencies including an SOS, cope with close calls and storms, and navigate diplomatic and neighborhood incidents en route to a safe outcome.