Following the events of 'Mephisto's Wrath,' Mara tries to find the key to traveling between realms in an attempt to save Trevor, who she believes to still be alive. Little does Mara know, Trevor is being controlled by the powerful cosmic being Annihilus who plans to finish Mephisto's task of destroying the Earth. Mara must once again pick up the hammer to save the planet, but this time she won't be fighting along side her brother - she will be fighting against him.