Dr. Stone › Saison 1 Dr. Stone : Stone World

Chapter 12 — Episode 12

The episode begins with Senku's group preparing to venture into a dangerous hot spring area to collect sulfuric acid, a critical ingredient for the sulfa drug needed to cure Ruri. Senku hands Ginro a silver spear, explaining that it will serve as a gas sensor — if the tip turns black, deadly toxic gas is nearby and they must flee immediately. The group sets off, following a river with no fish but covered in emerald-green moss, confirming they are on the right path upstream. In the middle of the episode, Senku makes the difficult decision to order Chrome to stay behind, arguing that if both scientists die, all scientific knowledge will be lost forever. Chrome refuses to accept this plan, insisting that two science users working together actually increases their survival odds, and emotionally confronting Senku for trying to protect him rather than treating him as an equal. Moved by Chrome's argument, Senku relents and agrees to make a second gas mask so Chrome can join him. Meanwhile, Kaseki reassures a frightened Ginro that being afraid is not weakness, and quietly crafts an extra gas mask, leaving it behind as if by accident. At the end of the episode, inside the toxic gas zone, Chrome spots that Senku's gas mask is dissolving at the base and alerts him just in time. Then Chrome's own mask fails, and Ginro — who had secretly followed with the spare gas mask — rushes in to save him despite his fear. Encouraged by Senku and Chrome to overcome his terror using his head and heart, Ginro steadies his breathing and drives away the threat. Finally, the trio successfully collects the sulfuric acid, celebrating their hard-won victory as a team.