A young wireless operator enlists and serves aboard Coast Guard cutters, learning seamanship and wireless work while confronting storms, derelict vessels, icefields, and wartime hazards. Episodes trace his growth through shipboard duties, daring rescues and searches for disabled craft, a mystery involving sabotage and a falsely accused crewman, and a climactic sinking in which wireless communication plays a crucial role. The narrative emphasizes practical procedures, crew discipline, and the courage of surfmen, interweaving action sequences with technical detail about wireless operation and life aboard small cutters, and concludes with the resolution of the mystery and the affirmation of duty and professional competence.