Ender's Game: Battle School #3

The legendary sci-fi epic by New York Times Bestseller Orson Scott Card continues as the children's training continues at Battle School, but Ender begins to question exactly who the enemy is. He's been isolated, his peers have been turned against him, and now he's been thrown into the deep end... transferred into an army of kids all much older than him. Even if Ender can make it through this, he's found a new game that he might not be able to beat. It's called the Giant's Drink, and no one's ever gotten out of it alive.