The expansion is set after the events of Warlords of Draenor and returns to the prime universe where heroes brace to defend Azeroth from a third invasion of the Burning Legion. To prevent a successful attempt to bring Sargeras back into Azeroth, heroes must retrace the steps of Maiev Shadowsong to the Broken Isles as she chased Illidan to the Tomb of Sargeras in hopes of finding some forgotten tools in their new fight, including the Pillars of Creation. They also need to find the new portal in the mysterious island chain that was opened by Gul'dan (a powerful orc warlock), who came from the alternate-timeline universe of Draenor. Players must be careful, as Gul'dan may know more about the region than potentially anyone who was still alive.