In the future, humanity is preparing to launch an attack on the homeworld of an alien race, called the
Formics, that had attacked Earth and killed millions. The Formic invasion was stopped by Mazer Rackham, who crashed his fighter jet into the Formic queenship at the apparent cost of his life. Over the course of 50 years, gifted children are trained by the International Fleet to become commanders of a new fleet for a counterattack. Cadet
Andrew "Ender" Wiggin draws the attention of Colonel
Hyrum Graff and Major Gwen Anderson because of his aptitude in simulated space combat so is recruited into Battle School. In the school he is placed with other cadets his age, but Graff treats him as extraordinary, thereby subjecting him to ostracism. The cadets are placed in squads and perform training games in a zero-gravity "Battle Room". Ender quickly adapts to the games, devising new
strategies older students had not contemplated. However, Ender is also annoyed that the leaders do not let students read their emails, as they believe it will distract them. Graff reassigns Ender to Salamander Army, led by Commander
Bonzo Madrid. Bonzo, disgusted that the replacement he asked for is an untrained student, forbids Ender from training with the rest of the squad. Cadet
Petra Arkanian takes him under her wing and trains him privately, much to Bonzo's chagrin. In the next match, Bonzo forbids Ender from participating in a battle between the Salamander Army and another team. However, seeing the team losing and Petra in trouble, Ender comes to her aid and helps Salamander Army win, regardless of the fact that he has disobeyed orders. Ender plays a computerized "mind game" set in a fantasy world, which presents difficult choices to the player. In one situation, Ender creates an
outside-the-box solution to overcome a seemingly unsolvable problem. Later, he encounters a Formic in the game, and then simulated images involving his psychotic brother,
Peter, and compassionate sister,
Valentine. Anderson notes these unusual additions to the game are seemingly altered by Ender's interaction with it. Graff promotes Ender to lead his own squad, which is made up of misfit students. They are put in increasingly difficult battles. In a surprise match against two other teams, including Bonzo's Salamander Army, Ender devises a novel strategy of sacrificing part of his team to achieve a goal, impressing Graff. After the match, Bonzo attacks Ender out of rage, but Ender fights back, resulting in Bonzo hitting his head and sustaining a serious injury. Bonzo is then briefly seen in the infirmary receiving emergency surgery, leaving his ultimate fate ambiguous. Distraught, Ender quits Battle School, but Graff has Valentine convince him to continue. The group's training is rigorous, and Anderson expresses concern over this, but Graff notes they have run out of time. Graff takes Ender to humanity's forward base on a former Formic planet near their homeworld to meet with Rackham, who explains that the Formics share a hive-mind mentality and how he exploited it to win the battle. Ender finds that his former squad members are also there to help him train in computerized simulations of large fleet combat; Rackham puts special emphasis on the fleet's Molecular Detachment (MD) Device that is capable of disintegrating matter. Ender's final test is monitored by several fleet commanders. As the
simulation starts, Ender finds his fleet over the Formic homeworld, vastly outnumbered. He orders most of his fleet to sacrifice themselves to protect the MD long enough to fire on the homeworld. The resulting chain reaction burns the entire planet. The simulation ends, and Ender believes the test is over. The commanders restart the video screens, showing that Ender's fleet was in a live mission, destroying the Formic homeworld. Despite Graff congratulating him, Ender becomes livid, having been tricked into killing a race that had never re-attacked Earth. While asleep, Ender is awoken by the Formic Queen and is directed to a Formic structure nearby as being similar to the ruined castle from the game. She acknowledges Ender's role in the genocide and moves to kill him, but when he shows remorse, she spares his life. The dying Queen gives Ender a Queen egg that she has been protecting. With the war ended, Ender is promoted to
Admiral, given a small ship, and left to his own devices. In a letter to Valentine, he confides that he is going into deep space, determined to find a suitable planet to start a new Formic colony with the Queen egg. ==Cast==