After players complete the Extraction story mission in Act 1 of Modern Warfare 3 - Zombies, Operation Deadbolt, they will unlock the second act of the new Zombies story. Act 2, Mother of Invention, will have players work to set up Dr. Jansen's lab and begin working against Zakhaev's Terminus Outcomes mercenary group by diving deeper into completing contracts, upgrading weapons, and earning kills, all while working toward the next story mission, Shepherd.