Dr. Stone Vol. 6 (manga)

Senku's father, the astronaut Byakuya, returned to Earth shortly after humanity turned to stone. What did he leave behind for his son to discover thousands of years later?

In the meantime, Senku and the villagers have to contend with attackers from the Tsukasa Empire. The dire situation calls for drastic measures, so they start work on their strongest weapon yet...