Graff arrives to revel to Ender he was being tested him and is still part of the program Graff brings Ender to battle school placing ender with other cadets his age but isolates him from the others.
ender finds his former squad members have been assined to help him train in computerized simulations of large fleet combat enders training is rigorous and major anderson becomes worried for welfare.
Enders final test is monitored by several of the fleet commanders. As the simulation starts, Ender finds his fleet over the formic home world and vastly outnumbered. he orders most of his fleet to sacrifice themselves to protect Petras MD device until they can fire at the home world. this results in chain reaction, which burns over the surface of the planet, killing the entire species.