Simplify the following text for a Grade 7 native English-speaking person.
Original: Upon learning of AndrÃ 's capture , Arnold fled down the Hudson River to the British sloop-of-war Vulture , narrowly avoiding capture by the forces of George Washington , who had been alerted to the plot .
Simplified: Upon learning of AndrÃ 's capture , Arnold fled down the Hudson River to the British ship HMS Vulture . He was almost captured by the forces of George Washington , who had been alerted to the plot .