Okabe travels back in time with Suzuha to just before Kurisu's death to witness the dawn of the time machine arms race and the spark of World War III.

On a calm day in Akihabara, Okabe and the other laboratory members are invited by Faris go to America. Mayuri and the rest are planning to reunite with Kurisu, who had come back to an American laboratory. A few days later, Okabe's mad scientist persona Hououin Kyouma arrives alone at the airport in Los Angeles, where he may be taking the first step to leading the world into chaos.