Regrouping in an emergency bunker, the League manage to retake the Watchtower, free J'onn and defeat Doomsday, before confronting the real Brainiac in his lair.
Alone on the Watchtower, J'onn is ambushed by Doomsday who takes him prisoner and takes over control of the Watchtower while Brainiac steals a Mother Box from the League's vaults. While Wonder Woman assists Superman in stopping the few White Martian vessels that managed to escape Mars and J'onn Jonnz returns to the Watchtower, the rest of the League (including any unlocked characters the player may have accessed by this point) work together to stop Grodd. Brainiac has also freed Gorilla Grodd from imprisonment, who intends to take revenge on his jailors and humanity with use of his Earthquake Machine. Superman and J'onn J'onnz travel to Mars to stop them from escaping but this has been yet another diversion from Brainiac who, anticipating their success, took the opportunity to steal vital equipment from the White Martians. However, the League realize it has been upgraded capable of breaking Earth's orbit, the missile has actually been fired at Mars in an effort to free the White Martians, who will invade Earth upon being reawakened.
