Episode: Steins;Gate - 24 - Achievement Point 375554

Picking up a light up sword in order to use its liquid as a substitute for Kurisu's blood, Rintaro and Suzuha return to the day of Kurisu's death. In order to prevent a Metal Upa toy that would prevent Nakabichi's paper from being destroyed by an on-board fire, Rintaro obtains it himself so that Mayuri ends up with a plastic one, which would later make its way to Kurisu and Nakabichi. Finding that the liquid in the gadget has dried up, Rintaro provokes Nakabachi into stabbing him, leading him to run off in fear with Kurisu's theory. After knocking Kurisu out with a taser, Rintaro uses his own blood from his stab wound and to recreate the scene he originally saw, fooling his past self and sending him on his time-hopping journey. As Rintaro returns to the present, Suzuha gives her thanks before she disappears, as she does not exist yet in the Steins Gate world line. After recovering his wounds, Rintaro starts giving out badges to the lab he recruited in other World Lines, saving one for Suzuha, who will be born in seven years. Later, while walking in the streets of Akihabara, Rintaro has a chance encounter with Kurisu, who appears to have retained some memories of the other World Lines.

Source: Wikipedia