Activision and id Software have revealed details on the upcoming expansion pack for the WWII first-person sequel, Return to Castle Wolfenstein.

Carrying the full title of Return to Castle Wolfenstein: Enemy Territory, this expansion will deliver a new one-player campaign, developed by Mac Dog Software and a host of new, and as yet unspecified multiplayer options, developed by Splash Damage.

Splash Damage has worked with id before, most recently in the delivery of several Quake 3 multiplayer mods.

Expect to see Enemy Territory on shelves towards the end of summer.