By late 1944, as the Allies march toward the Rhine, it becomes clear that Germany is headed for defeat. American Col. Devlin, Gary Merrill, leads a small, purposefully crooked brain-trust that recruits German POWs to slip back across the lines and spy on their former comrades. A cynical mercenary named Tiger, Hans Christian Blech, and a young, idealistic medical student named Happy, Oskar Werner, are two such recruits. Joining them is Monique, Dominique Blanchar, a former resistance operative who trains Happy and the others in the tricks of espionage. The trio’s work grows urgent when Devlin learns that a Wehrmacht general wants to negotiate the surrender of his entire command, and a mission must be mounted to verify and support that move. The plan falls to Lt. Dick Rennick to lead, with Tiger providing his field knowledge and Happy handling a parallel objective to locate the elusive 11th Panzer Corps. They all parachute into Germany and split up to maximize their chances of success.
As Happy threads his way through a country still filled with danger and doubt, he encounters a spectrum of attitudes toward the war. On crowded buses and quiet trains, in guest houses and smoky taverns, he meets stubborn defiance and weary resignation alike. Some are still determined to fight, like the SS courier Scholtz, Wilfried Seyferth, while others have already surrendered to the reality of defeat. He also crosses paths with Hilde, Hildegard Knef, a war widow who has become a prostitute, embodying the human toll of the conflict. These meetings reveal that courage and compromise coexist in a war-torn land, and that personal choices can tilt the balance between loyalty and survival.
Happy eventually locates the 11th Panzer Corps, posing as a medic and gaining access to its commander, Oberst von Ecker, O.E. Hasse, at his castle headquarters. The mission pushes forward, and Happy narrowly escapes capture by the Gestapo, slipping away to a ruined Mannheim where Rennick and Tiger have taken shelter. The trio learns that the German commander they hoped to reach has supposedly been wounded and is now under SS guard in a hospital, a fact that complicates any surrender and makes the renegotiation feel fragile at best. With their radio knocked out, the three improvise, moving toward the Rhine and a daring crossing to American lines.
As they approach the river, Tiger falters, his nerve deserting him at a critical moment. Rennick is forced to take decisive action—he must neutralize his companion to keep the mission from being exposed. The plan shifts again as Rennick and Happy prepare to swim across to safety, but they are spotted just as the crossing begins. In a final act of sacrifice, Happy surrenders to draw the fire away from Rennick, buying him a chance to reach the far shore. The risks and sacrifices pay off in the end: Rennick survives, but his earlier sense of treason is unsettled by the realization that loyalty and duty may hinge on imperfect judgments made under impossible pressure. The mission has transformed him, reshaping his view of betrayal, courage, and what it truly means to stand by one’s country when every choice is shadowed by fear and doubt.
