After two American Revolution adventures, Patrick and Beth regret not meeting General George Washington. Their goal is to meet him. They land in a tree near a large military camp. Farther away, they see a river and a bay. Tall ships are anchored in the bay. The cousins can’t tell whether the ships are British or American.
A teen girl happens by and asks for their help in carrying the general’s laundry back to headquarters. Patrick and Beth assume she means General Washington and are glad to help. The girl introduces herself as Sally.
They walk toward the firing cannons. Sally explains that the cannons move closer every day. She takes them to a cave in the side of a cliff. The troops have dug these caves to protect themselves from cannon shells.
The cousins hear General Cornwallis telling his men that they are escaping that night. Patrick and Beth realize they are in a British camp, not with General Washington’s army. General Cornwallis mentions Yorktown, and the cousins realize they are in the town where the British surrender will happen at the end of the Revolutionary War.
The general doesn’t have enough ships to hold his men, but he has many small boats that they can use to cross the river. He wants to keep the Americans from discovering his plan. He sends a courier named James Armistead with a message to General Washington, saying he wants to discuss surrender. He hopes his letter and future negotiations will allow his men the time they need to escape in the rowboats.
The children are told to report to Colonel Lake and help him watch for stowaways on the docks. Seeing the children upsets the colonel. He wants a guard, not children. Colonel Lake shows the cousins where to hide to spot anyone trying to escape in a boat.
The children leave their hiding spots. They want to warn General Washington about the British’s plans. But Patrick and Beth are grabbed from behind. Once they promise not to scream, they learn the first man’s name is Samuel. His friend looks like an escaped slave.
Many slaves have run away from their plantations to join the British because the British promised them freedom. However, with the British leaving Yorktown, this slave’s master will come looking for him. He has to leave.
They let his friend take one of the rowboats without reporting it missing. Samuel tells them that there are more stowaways coming. Then the first British transport boat lands at the dock. Patrick and Beth realize that if the British flee Yorktown, the war won’t end. Patrick and Beth pray that God will keep the British from leaving so the war can end.
Just then a bolt of lightning hits the water and rain begins to fall. Thunder from the storm rocks the dock. Samuel leaves to warn other runaways not to try to cross the river because of the storm. The British boats that were headed to the dock turn back. It’s too dangerous to cross. The cousins realize that God answered their prayer.
Patrick and Beth decide to find General Washington the next morning, after the storm has subsided. Beth finds a map of Yorktown, and they plan their route. They slip out of Yorktown and into the woods. When they cross open ground, they hide in the deep holes made by cannon balls. The cousins get very close to the American side.
But then they see a man hiding behind a boulder. They recognize him as Armistead, the courier they saw in General Cornwallis’ cave. They watch him stuff papers into his boot and decide to investigate. He glares at them, but Patrick and Beth hide behind the boulder with him.
They tell him they are trying to get to the American side. He doesn’t trust them because he saw them with the British. The cousins don’t trust him either, but say nothing.
The American cannons start shooting again. Armistead tells them that the shelling will go on all day. He says the Americans are trying to force Cornwallis to surrender because he can’t escape with his troops. When asked which side he’s on, Armistead says he’s on the side of safety.
He leads the children away from the boulder to find shelter. The children realize that Armistead is leading them back to Yorktown. When he leaves them, they follow him.
Once on the American side, they spot him chatting with two soldiers in white uniforms. He then walks into a large white tent. Patrick and Beth think it must belong to Washington, so they run to it to warn the general.
Inside, they see four soldiers in white uniforms standing around a table with a tall young man in a blue uniform. No one looks like Washington. The soldiers begin talking in a language that sounds like French.
Two guards try to grab the cousins, but Patrick and Beth escape and end up in the woods outside the camp. They are safe from the French, but cannon balls hit close to them. They hide in a small thicket with a sandy floor. Patrick explains how the French didn’t want the British to get too powerful so they joined the American cause. They find they are hiding on an anthill so they leave it, and a skunk sprays Patrick.
They head to the river to get Patrick cleaned up and see a British ship get hit by a cannon ball and explode. They find a British uniform. Patrick washes up and puts on the uniform, which doesn’t stink like skunk.
Armistead captures them, and they all return to Yorktown. They arrive at Cornwallis’ cave. Cornwallis asks what Armistead has been doing, and Armistead tells him that he did as instructed and delivered Cornwallis’ letter to the Americans. He says the Americans did not believe the letter and knew that Cornwallis was trying to delay them in order to escape.
Cornwallis wants to know why the children are there. Armistead introduces Patrick as a drummer. They need one for the surrender. Patrick tells Cornwallis that the British can’t win because the Americans are well supplied with provisions and ammunition. The cousins realize Armistead is a spy for the Americans.
Patrick is given a drum and two sticks. Beth is asked to play a fife. Cornwallis has decided to surrender. He sends his top man, Officer Mudge, to negotiate the terms of the surrender. The cousins follow Mudge, who is holding a white handkerchief. Patrick starts playing the drum, and Beth plays the fife. The cannons stop firing.
The Americans cheer. An American soldier approaches and takes Mudge to the American commander. One officer is taller than the others. Beth recognizes him as General George Washington.
Washington agrees to a two-hour cease-fire while General Cornwallis writes a formal proposal for surrender. Mudge is returned to the British. Patrick and Beth choose to stay on the American side. General Lafayette praises Armistead, a spy who has been working for him. Armistead has been a double agent, working for the Americans and supplying the British with false information.
Everyone kneels. Washington prays to God with his men and thanks Him for bringing the war to a close. After the prayer, Beth and Patrick return to Whit’s End in the Imagination Station.