Dr. Stone Season 4 Episode 1 recap: Senku and Ryusui come to blows

The Kingdom of Science will soon be no more, with Science Future being the last in the franchise. Dr. Stone Season 4 Episode 1 is a long way from the end, though – here’s everything that happened.

If you think of legacy anime, titles like One Piece, Dragon Ball, and Naruto likely come to mind. Dr. Stone is right up there with the best, though it’s soon to come to an end after its fourth season.

Let’s briefly bring you up to speed. Thousands of years ago, the people of Earth were turned to stone. Senku spends his days reviving anyone he can and now has a goal to defeat those responsible… who just happen to be on the moon.

That’s the overarching premise, though I’m skipping over a lot of detail. If you’ve got yourself up to speed with the last three seasons, here’s the full debrief of Dr. Stone Season 4 Episode 1. Warning: spoilers ahead!

The New Voyage begins in Dr. Stone Season 4 Episode 1

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By the time we meet back up with the gang in Dr. Stone Season 4 Episode 1, their journey to North America is well underway. They’re aboard the Perseus having set sail from Tokyo, with Minami Hokutozai asking everybody how they’re feeling about the adventure ahead. She’s recording everything on a urushi lacquer-coated wood cylinder (that’s important later on).

Gen, Suika, Chrome, Kaseki, Kirisame, Kinro, and Matsukaze are all in attendance, with Tsukasa joining the team. Remember – while he was previously an antagonist who worked against the Kingdom of Science, his revival from a stony death mellowed him out enough to disband his empire and join Senku’s vision.

Ginro’s been brought along for the ride too thanks to Matsukaze, although is hating every minute of it.

Ryusui challenges Senku’s authority

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When we first see Senku and Ryusui, they’re at loggerheads. Ryusui believes it will take 70 days to reach the US, while Senku believes it can be done in 40. When Taiju tries to get them to stop fighting, each tries to present their thinking to the rest of the crew.

As far as Ryusui sees it, the best way to get to their goal end destination – San Francisco – is to go by a route known as the Rhumb Line. It essentially goes directly across the sea from one location to another, meaning the crew is under the least amount of stress and exhaustion possible.

However, Senku disagrees. He thinks the crew should sail the Great Circle Route, which looks longer when it’s laid down on a flat map. Getting the group to measure the distance between the two on a globe, he’s proved right. By sailing in a curve, they could shave 30 days off their route, but Ryusui believes that puts the crew at severe risk.

Neither will compromise on their thinking. Senku believes they have a 40-day window to get the corn provisions they need for the mission… otherwise, it’s game over. Ryusui says if Senku goes through with his plan, he’ll intervene for the sake of the others. This leads to the two dueling – the winner gets to charter their route.

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The duel isn’t exactly what anybody anticipated, though. Both are playing poker, with Ukyo acting as dealer. Senku chooses to play with Kohaku, while Gen teams up with Ryusui. Away from the table, the rest of the crew is even split over who they think will win.

As the game starts, Kohaku accuses Gen of carrying the deck around with him. She correctly predicts that the ace of hearts is the first card in the deck, causing her to ask Ukyo to keep Gen away from the deck.

Senku and Ryusui are neck-and-neck as the game progresses, though Ryusui has a few more chips. Kohaku believes something has been sprinkled over the deck, which Gen denies (though he has a Kanabun beetle in his sleeve). While Senku and Kohaku inspect the deck, Ryusui raises all his chips.

Senku gets his own way in the end

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Senku believes the bug and card check gave Gen enough time to completely switch out Ryusui’s cards altogether. He tries to predict exactly which cards from the deck he needs to win with a straight flush, then matches Ryusui’s all-in bet. Kohaku quickly draws cards from the middle of the deck, though this is almost too fast to be proved.

Senku finishes with a royal straight flush, revealing he already used transparent urushi lacquer (left over from the recording device) to mark the edges of the cards he knew he’d need. There’s a trade-off to winning, though. Senku is allergic to the lacquer, meaning his face blows up like a fish as soon as the game ends.

This means the Great Circle Route is the one the crew will use, and Ryusui concedes on one condition. In order to make sure the crew is well looked after, they create a leisure zone on deck, complete with its own casino area and bar. Complete with food, this means they lose the 30 intended days.

Ukyo thinks everything worked out in Senku’s favor a little too well, theorizing that Gen had planned this whole fiasco using his mentalist skills. As you’d expect, Gen completely denies this.

Dr. Stone Science Future (aka Season 4) is now streaming on Crunchyroll weekly. While you wait for the next episode, check out the most underrated anime of 2024, the most anticipated anime of 2025, and Solo Leveling Season 2’s release schedule.