The film tells the story of a car mechanic in Berlin-Reinickendorf, who decides to modify his car to hide a passenger within a modified engine compartment to help them escape to freedom in West Berlin. BMW's film is based on the true story of Klaus-Günter Jacobi, who helped his best friend flee East Germany by smuggling him across the Berlin Wall in a BMW Isetta. On the evening of May 23, 1964, a few minutes before the border closed at midnight, Jacobi drove his BMW Isetta with his childhood friend, Koster, tucked inside.