On July 2, 1863, the hill now called Little Round Top had no settled name; soldiers called it Rock Hill or Sugarloaf. This episode starts with its geology, a boulder-strewn diabase spur about 150 feet above Plum Run, and then follows how it was left empty when Daniel Sickles moved the Third Corps forward to the Peach Orchard without orders. John Bell Hood’s Confederate division drifted toward the Round Tops, pulled by Devil’s Den, Union sharpshooters and broken terrain, while Hood’s wounding left Evander Law unaware at first that he commanded the division.

Gouverneur K. Warren spotted the glint of bayonets from the summit and sent aides, including future Brooklyn Bridge builder Washington Roebling, to find troops. Colonel Strong Vincent intercepted one messenger and rushed his brigade to the hill about ten minutes ahead of the attackers. Beyond Joshua Chamberlain’s 20th Maine, the episode covers the near-collapse of the 16th Michigan, Vincent’s mortal wound, Patrick O’Rorke’s charge, cannons hauled up by hand that could not depress to fire downhill, and historian Garry Adelman’s math on whether losing the hill would really have lost the battle.

• The 15th Alabama arrived after a 20-mile march in July heat with empty canteens.
• Chamberlain refused his line into a V and, after 90 minutes and out of ammunition, ordered the bayonet charge.
• Lieutenant Holman Melcher started a spontaneous charge, and Captain Walter Morrill’s hidden company fired into the retreating Alabamians’ flank.
• General Stephen Weed was shot by a sniper, and Charles Hazlett was killed while leaning over him to hear his last words.
• Adelman calculated that at most about 2,650 exhausted Confederates could have held the summit against 11,600 fresh Sixth Corps troops a mile away.