Twin Peaks is the seventh installment in the Great Battles of the American Civil War (GBACW) series, published by GMT Games. Two full battles are included:

Cedar Mountain
August 9th, 1862. With the Peninsular Campaign winding down, Gen. Robert E. Lee sent Maj. Gens. Stonewall Jackson and A.P. Hill to attack Maj. Gen. John Pope's new Federal Army of Virginia with 27,000 troops.

Gen. John Pope, hoping to draw attention away from Maj. Gen. George McClellan's withdrawal from the Peninsula, moved against the rail junction at Gordonsville, Va. Stonewall Jackson found USA Maj. Gen. Nathaniel Banks's division isolated. Jackson crossed the Rapidan River to engage. Pope ordered Brig. Gen. Franz Sigel's division to unite with Banks's forces on high ground near Cedar Run, seven miles south of the town of Culpeper. These two forces met in the afternoon heat.

South Mountain
September 14th, 1862. After the CSA success at Second Bull Run Gen. Robert E. Lee believed the demoralized USA armies could not respond to any bold action. Thusly, he planned a campaign to raid Maryland and Pennsylvania and to threaten Washington D.C. itself. Once again Lee confidently divided his army to both move north and neutralize the large Union garrison at Harper's Ferry.

However, the Union Army under Gen. George B. McClellan was quick to recover from the Bull Run defeat and was already in pursuit of Lee. The gods of war smiled on the Union troops as a copy of Lee's orders fell into Union hands. An attack through the lightly held gaps at South Mountain would cut Lee's army in two and perhaps end the war. At 6:00 am the Union Army moved.