"Promotions or a coffin!" To George Armstrong Custer, war is the Devil's own fun. And his luck—"Custer Luck"—peaks during the Civil War, keeping him alive against all odds. Yet, for the first two years of the war, Custer luck has not earned him a command—until, three days before a brewing battle at Gettysburg, Captain George Custer is promoted to brigadier general. Possessed with raw courage, rare gallantry, and reckless heroism, Custer becomes the youngest general in the Union army.

Hugely spirited, tactically flexible, and fiercely ambitious, Custer, on July 3, 1863, trots in front of the First Michigan cavalry regiment, grips his sheathed saber, and pulls. The blade swishes from its metal scabbard with the sleekness of a swooping hawk. "Come on, You Wolverines!" he yells. And the 23-year-old leads one of the greatest cavalry charges in the annals of warfare.

Craving attention, approval, and glory, the boy general with long, flowing, golden locks is an impulsive, fearless daredevil. Commanding the Michigan Cavalry Brigade, Custer is throttled by his vainglorious reporting senior and ridiculed by battle-hardened Wolverines. But the pride that lies in the flesh of all men is thicker in Custer. He loves dancing at the edge of death's doorstep. And he believes that moral courage means leading from the front—but not always following orders. Because he knows that, between orders and duty, blind obedience and justified defiance hang in the balance.

Thundering Courage is the riveting story of the Union cavalry's Second and Third Divisions at Gettysburg, boy generals who face crises of justified defiance, and the unsung hero who wisely keeps a human thunderbolt on a tight, short string. Built firmly upon the annals of history, Thundering Courage journeys through the hearts and minds of Union cavalry heroes who face the agony of choosing between blind obedience and justified defiance at the Battle of Gettysburg.