Steppenwolf discovered that Superman's death somehow managed to reactivate the three Mother Boxes. Willing to regain the favor of Darkseid, Steppenwolf traveled immediately to Earth with his army of Parademons to retrieve the Boxes and destroy the planet under the orders of his nephew.
Firstly, Steppenwolf went to Themyscira, where the first Mother Box was located. He appeared at the Penetralium where the Amazons stored the Mother Box. Despite the Amazons' efforts to escape with the Box or at least avoid Steppenwolf's destruction over the island, their defending ultimately failed. Queen Hippolyta attempted to escape with the Mother Box after sealing Steppenwolf inside the chamber, but Steppenwolf not only slaughter several Amazons and her horses after escaping from the chamber with some of his Parademons, Steppenwolf escaped from the chamber and retrieved the Mother Box before Hippolyta and her Amazons could do anything, so Hippolyta contacted her daughter Diana to advise her of Steppenwolf's arrival to the Earth.
At the Louvre, Diana watched a news report showing a signal fire burning at the Shrine of the Amazons and knew that it had been sent by her mother to warn of the impending invasion. Soon, she traveled to Gotham to tell Bruce Wayne about the incoming invasion and the story of the first invasion of Earth. Steppenwolf then teleported to Atlantis to retrieve the second Mother Box.