Dr. Stone Season 4 Episode 1 English Dubbed Episode Title: Ryusui vs. Senku Episode Description: Ryusui and Senku argue over which route to take to America. Ryusui believes that the voyage will take 70 days on the easiest route known as the rhumb line, while Senku believes that it will take 40 days on the quickest but hardest route known as the Great Circle Route. Senku wants to make it to America quickly in order to harvest the corn on time, otherwise if they arrive too late, it will already be winter, and they won't be able to make any revival fluid until next fall, which is a waste of time...