In this episode, we pick up with Senku still in a flashback. After waking up from his petrification, Senku solidifies his goal to rebuild civilization. He discovers that something in the soil aided his awakening and follows the source back to the bat cave we saw earlier in the season.
The bat cave has a liquid dripping from its ceiling. Senku believes that it had a significant part in his awakening so he gathers an amount and pours it on a nearby body that happens to be Taiju.
When the petrification does not immediately wake Taiju up, Senku revisits his theory to figure out what other components could be involved in the awakening. This leads him to use Albert Einstein’s special-relativity equation, E = mc2. Senku uses the bat juice along with igniting the consciousness of Taiju and he wakes up.
Senku wakes up in real-time.
Two Nations of the Stone World
After Senku wakes up, Yuzuriha put a wood plank to his back to protect his spine and neck. Senku is unbothered by almost dying and decides to use his presumed death to get the upper hand on Shishio.
Shishio thinks Senku is dead, so Senku proposes Taiju and Yuzuriha go and join his ranks to act as double agents and thwart his plans to create his perfect youthful world.
At the same time, Senku will go to find the people who sent up smoke signals to begin his community of science.
When we next see Shishio he is approaching the bat cave when he is attacked by a girl. He identifies her as a 2nd generation human born after the petrification. He categorized her as primitive and planned to take over her clan at a later time. He traps her under a tree and proceeds to his destination.
Senku comes to rescue her. She is enamored by Senku’s ability to get her from under the tree using science. He used a pulley system. We find out her name is Kohaku and she vows to be with Senku.