Based on a totally true story during the Civil War, Buster Keaton plays Johnnie Gray, a talented train engineer from the South. He has two loves of his life – his girlfriend, Annabelle, and his engine.
Since this is set in the 1860s, Johnnie must court Annabelle instead of swiping right. Annabelle’s father and brother catch wind that a war has begun, and the two enlist in the Confederacy. They guilt Johnnie into enlisting too.
The Confederates determine Johnnie has more value as an engineer, so they deny him entry as a soldier. Johnnie doesn’t know why the military rejects him, but Annabelle’s family think he’s a coward, plain and simple. Her family forbids Annabelle from touching Johnnie ’s engine ever again.
A year into the war, Johnnie is still an engineer on The General. The Northern Army’s Captain Anderson hatches a plan to steal Johnnie’s engine. After that, they’ll head north, take out the Confederacy’s telegraph network, and damage any railroad tracks they can; disrupting the South’s supply lines.
The North successfully steals The General, and they somehow manage to capture Annabelle in the process.
Johnnie and several townspeople take chase, but they stop following as Johnnie runs off into the distance. Johnnie soon learns he’s on his own, so he uses a handcar, and then a wooden boneshaker bicycle to reach another near-identical engine to his beloved General called The Texas. While Johnnie remains in hot pursuit, Northern spies dismantle telegraph wires, and sabotage the tracks in hopes of stopping him.
At one point, Johnnie picks up a large cannon, but it’s more of a danger to himself than to anyone else. Through many spectacular life-threatening stunts, Johnnie finally closes in on the spies, only to realize he’s driven deep into enemy territory. He abandons The Texas to escape with his own life.
Later that night, Johnnie sneaks into the North’s headquarters, and overhears a surprise attack they’re planning on the Confederates. It’s then he realizes Annabelle is a prisoner in the house he’s at. Using his quick wits and many clever costume changes, Johnnie rescues Annabelle, and then steals back The General. They race home to tell the South of the attack before the North can ambush them.
As our heroes head back on the path they just came, the spies on The Texas, as well as the entire Northern army, pursue Johnnie and Annabelle. The two set many booby traps to slow down the bad guys. At one point, they switch rails, and find themselves behind the North, but then race ahead. Finally, they set fire to the train tracks past the river, and arrive at the town to tell the Confederates about the impending attack.
When the North finally attacks, the Confederates are ready. In a large battle sequence across the river, the North drives The Texas over the bridge. As the huge engine chugs forward, to everyone’s surprise, the bridge disintegrates. The entire twenty-ton engine falls into the raging river below, and the disaster turns the tables of the battle. Johnnie joins in the fight, and almost single-handedly defeats the North.
Once the North retreats, Johnnie receives a hero’s welcome, but it’s for the soldiers; not him. As he disappears into the crowd, he realizes he accidentally captured a 4-star General from the North on his engine. He begins marching his prisoner away, but a Southern general stops him, and takes him aside. In front of Annabelle and her family, he commissions Johnnie as a Confederate soldier, and gives him the rank of Lieutenant for his bravery. The boy finally gets his girl…and his engine.