In Dr. Stone Episode 12, "Buddies Back to Back," the Kingdom of Science risks lethal, gas-filled conditions to harvest sulfuric acid from a volcanic lake, essential for creating the sulfa drug. Senku utilizes silver to detect toxic hydrogen sulfide and improvises charcoal gas masks to survive the deadly "valley of death". For more details, visit Anime News Network . Review: Dr. Stone Episode 12 – Best In Show