George R.R. Martin's a Game of Thrones #20

Battle is joined at the Trident, with Tyrion Lannister in the vanguard-placed there by a father determined to rid himself of an embarrassment. But the fortunes of war are not so easily manipulated, as Lord Tywin is about to learn, to his great regret . . . and even greater rage. For in a brilliant tactical move, the host of young Robb Stark has descended upon the army of Jaime Lannister outside the besieged gates of Riverrun, and has won a great victory . . . and a prize that might end the war before it has fairly begun.