Biggles becomes involved in three undercover operations in this third bumper omnibus edition of his classic adventure stories. Biggles Secret Assignments take him from the icy wastes of Antarctica to remote regions of China:
- hunting a Second World War German submarine loaded with stolen gold
- battling with desperate villains over an ice-bound treasure ship
- tackling his arch enemy Erich Von Stalhein and teaming up with Gimlet King's special forces unit undercover in China