The official prequel novel to Independence Day: Resurgence.
Cities were crushed by the falling spacecraft - but one ship didn't crash. It remained intact, and disgorged hordes of alien soldiers determined to fight to the death.
The abandoned vessels also contained a wealth of advanced technology. Led by David Levinson, the greatest minds of our world developed deadly new hybrid weapons. Bases were built on the Moon, Mars, and beyond.
A new generation of defenders had to be trained, for the invaders would return. In the headlong rush to prepare, however, not everyone would survive...