The story begins with Rintarou Okabe and Mayuri Shiina attending Nakabachi's press conference about time travelling. His presentation angers Rintarou, who accuses him of plagiarizing John Titor's research. He loses his temper and yells at Rintarou, ordering him to stop. He is not seen again after that.
At the very end of the plot, Rintarou, along with Suzuha Amane, time travels back to the day of the conference to prevent Kurisu's death. It is revealed that his real name was Shouichi Makise, and that he is Kurisu's father. He attempted to murder her to steal her research on time-travelling. Rintarou tried to stop him, but unintentionally stabs Kurisu himself.
The research documents was later saved from a plane fire by Mayuri's metal Upa, which triggered the metal detector. Knowing this, Rintarou arranges so that the Upa put into the envelope by Kurisu is a plastic one. The metal detectors did not go off and the papers got destroyed by the fire, foiling Shouichi's plan.
Though it was not mentioned, it is likely that Shouichi worked with SERN in their time-travelling research.