Stone World The Beginning

With Senku seemingly killed after Tsukasa delivers a fatal blow to his neck, Taiju and Yuzuriha use his gunpowder to set off an explosion around Tsukasa, allowing them to escape. Realizing that Senku wouldn't simply sacrifice himself, Taiju and Yuzuriha discover some petrification on his neck, giving them the opportunity to heal the injury by using the revival fluid. Meanwhile, a flashback shows how Senku first emerged from his petrification and developed the tools needed to survive.