While continuing to use the hot air balloon to search for the oil, it's decided that Ishigami Village needs to take up agriculture to prevent future food shortages, as well as to produce preserved food for their upcoming sea voyage.

Kohaku has located the treasure left behind by Byakuya and the others, but it's encased in concrete. Senku has to devise a plan to quietly get at the contents inside, so as to not alert the guards.