Benedict Arnold was an American hero - right up to his betrayal of the Continental Army. He had fought bravely and against hard odds in the first years of the war of independence. He led the force that attempted to take Quebec, and take Canada into the United Colonies. He risked his life and lost his leg, bravely fighting for America (Battle of Quebec). But he was criticized and felt unappreciated and humiliated by the Continental Congress. He married a loyalist wife. Arnold had been found guilty of misconduct for some of his actions while in command of the force sent to Quebec. He was merely reprimanded by George Washington, who still needed him, but he never forgave the Congress. Arnold asked for the command of West Point on the Hudson River.

West Point was considered crucial to both the British and the Americans. If the British could sail up the Hudson River, they could effectively cut the colonies in to, giving them a great advantage. West Point and Constitutional Island were critically located.

In order to get around West Point to pass up the river, ships had to stop, get out the rowboats and pull the ship through. Americans forged a chain which crossed the Hudson between West Point and Constitutional Island. The chain weighed 65 tons and, was 500 yards long, and required 40 men four days to install. The chain floated on rafts assembled from four 16' sharpened logs, anchored between Constitution Island and West Point. A log boom was placed in front of the chain, but was later removed. Whether or not the chain would have withstood a strong, loaded British ship is not known, but the British chose not to take the risk.

Artillery placed on west Point and the island made the river impassable at that point. A ship trying to pass would snag on the chain and the artillery would destroy them.

Washington put Arnold in command of West Point and Arnold then offered West Point to the British in return for 20,000 pounds. He systematically weakened West Point by sending out detachments of soldiers on missions. He ensured that it would be at its weakest when the British attacked. He sent a spy going by the name of John Anderson to the British carrying detailed plans of West Point. The spy was captured. The patriot soldiers, not knowing of Arnold's involvement, sent a message to West Point telling Arnold what had happened. He immediately left and escaped to the British. Coincidentally George Washington had decided to visit West Point. Arnold, surprisingly, was not there so Washington helped himself to some food and waited. He received the news of the captured plans while there. Washington recognized the handwriting of Benedict Arnold and knew that they had been betrayed.

The British never really trusted Arnold after that, though they gave him a command of British troops. He and his wife went to England after the war, where he died, the most famous traitor in American history.