what was the main problem of chapter10?

They are basically being attacked by monsters in this chapter. They get on the bus and watch three old ladies get on behind them, and Percy notices that one of them is Mrs. Dodds. The three Furies are on the bus with them. Percy puts on Annabeth's invisibility cap and sneaks to the front of the bus, but then the Furies transform and begin a fight. Percy hits the emergency brake and stops the bus, and then manages to slice the Furies except Mrs. Dodds and make them disintegrate. Percy, Annabeth, and Grover run quickly away from the bus, leaving all their money, food, and clothes behind.