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.

The Kingdom of Science will need rations to last them through their voyage to the other side of the world. But Senku, being no professional, burns all the bread he attempts to bake.

Senku, brings along a team to look for the Sagara Oil Fields. Meanwhile, Suika and Francois go truffle hunting.

The morse code signal reading "WHY" saturates the airwaves too much for Ukyo to pinpoint a direction, so the Kingdom of Science works on a way to visualize the signal.

Kaseki's efforts to build the science vessel Perseus hit a roadblock when he realizes that it's impossible to get all the parts to fit in practice.

The Perseus crew are on their way to the treasure island, the birthplace of the Hundred Tales, where they hope to locate the treasure box left behind by the Soyuz crew.

The Perseus arrives at the treasure island. A recon squad consisting of Senku, Soyuz, Kohaku, and Gen set off to locate the platinum and make contact with the islanders. Ukyo later discovers something on the seafloor and send Ginro to investigate.

Amaryllis explains how she evaded petrification and how she came to her decision to sneak into the inner palace.

Suika and Ginro work together to rescue the mobile lab from the Perseus. Reunited with Senku and the others, the group works on items to help Kohaku with the selection process.

Amaryllis, Ginro and Kohaku are chosen to join the inner palace. The science team will need a way to communicate with them in secret, and, eventually, a way for them with the science team.

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.