From the liner notes

Inch by harrowing inch, The Tunnel tells the incredible true story of a massive underground escape attempt from East to West Berlin. Anti-communist East German swimming champion Harry Melchior (Heino Ferch) narrowly escapes the Communist regime just after the Berlin Wall is completed, and is determined to rescue his beloved sister, whom he was forced to leave behind. This international award-winning drama is a gripping and suspenseful thriller in the heroic tradition of The Great Escape.