From the introduction
"This is a simulation game of US strategic bombing raids from England and Italy on 25 February 1944, the last day of the `Big Week' offensive. Two or three players or teams direct the actions of the opposing air forces as they seek to inflict more damage than they suffer in this attritional contest."
UB Bombers from England and Italy move steadly towards their German targets while the US fighters seek to keep then protected from German fighter attack. Simple machanics mean the game is easy to learn, but the differing ranges of the fighters and speed of the bombers mean planning ahead is required. Not knowing when the Germans may attack and cause the fighters to drop their fuel tanks, and so have to return home make this harder than it sounds.