Modiphius Entertainment Achtung! Cthulhu 2d20: Mission Dossier 1 - Behind Enemy Lines - Expansion Book, Roleplaying GameThis first Mission Dossier for Achtung! Cthulhu 2d20. Requires the Achtung! Cthulhu 2d20 core books to play. Contains the first five adventures released following the RPGs launch. A brand new, never seen before mission, Operation Eastbourne. You can use this compilation to send your agents on a rip roaring rollercoaster ride through the first thrilling phase of the Secret War. All our games are designed to be: Accessible easy to learn and approachable