A self-described mad scientist attends a lecture on time travel, stumbles upon the dead body of a familiarly unfamiliar woman, and discovers that his text messages are no longer bound by the rules of space and time.

Okabe needs to find a very old computer to hack a very new tech.

The part-time warrior from downstairs tells Okabe about the search for her missing father. Meanwhile, the aspiring mad scientist is troubled by a mysterious text message.

In a further attempt to rescue Mayuri from her fate, Okabe reveals Ruka's past to her. Ruka must make a difficult decision that might change her entire life.

Tasked with preventing an impending World War III by an alternate Suzuha, Okabe finds himself playing an active part in Kurisu's death.