Set in the turbulent 1940s, Sara Holden and fellow Communist Underground members move in secrecy, risking all to deliver telegrams across Riverbend and Eastbay. As they protect democracy advocates and evade Nationalist agents and foreign spies, each mission brings them closer to the birth of a new nation. Their courage is passed on to the next generation, and in the Red Exhibition Hall, students remember an era shaped by sacrifice, belief, and unwavering resolve.