Dr. Stone Science Future Part 3 Episode 4 Review: A Big Shift In POV

Dr. Stone Science Future Part 3 released its fourth episode on April 23, 2026, introducing a shift in POV. While the episode showed us more inventions, it was primarily centered around the brothers: Ryuusui and Sai.

The episode did a good job at moving the story forward – without actually moving it forward. Even if there are just a few more episodes left in this anime, providing an emotional basis for the characters is essential, and this episode did it really well.

TITLE	Dr. Stone: Science Future Part 3
RELEASE DATE	April 2, 2026
STUDIO	TMS Entertainment
WHERE TO WATCH	Crunchyroll
MAL RATING (as of April 23, 2026)	8.29 / 10

Senku Ishigami Finally Invents a Computer

The episode started off with Taiju and Ukyo returning to North America aboard a smaller ship to wake everyone from petrification. Following that, they were all immediately hit by the news that Senku is making a computer. Usually, Senku makes a lot of things that become less and less relevant, but a computer might be the most meaningful invention.

In the previous episode, when Senku and Ryuusui finally managed to wake Sai, the genius mathematician, they realized that mathematics was not the only thing he was good at. In fact, he can write machine code from his memory. That means, in order to fully unlock the potential of this new companion, they need to make a computer in the stone world.

It was a really emotional moment for Sai when he saw a very simple computer circuit working for the first time in 3700 years. Senku gave him full leadership in making computers, and they decided that the colony in America needs to make its own computers as well. That led to the invention of actual fax machines, which allowed Taiju and everyone to send a group photograph all the way to India.

Ryuusui Just Wanted To Be With His Brother

During that exciting moment, Ryuusui and Sai were weirdly silent. Usually, Ryuusui would’ve been very excited and thinking of how to monopolize this new invention; however, he just stood right next to his brother in total silence, which was something Gen noticed as well.

Later at night, Gen decided to visit Sai, hoping to get some answers, to learn if they had some sort of trauma with the group photos. While he couldn’t bring it up, it was Chelsea who shamelessly asked Sai if they had a trauma or something. Sai mentioned how Ryuusui and Sai were never part of the family group photos. Sai was being trained like a mathematics soldier, and no one could control Ryuusui.

Sai also remembered how Ryuusui was always bothering him, ordering him around all the time. To that, Gen expressed how it could be that Ryuusui simply wanted a close older brother. Following that, Sai played his first game of Chess with Ryuusui, and Ryuusui mentioned how it would be really lonely at the ship without Sai.

Sai, after hearing Ryuusui’s honest words, decided that he would join the crew to go around the world, which was something that he had not initially planned.

Dr. Stone Science Future Part 3 Episode 4: Final Verdict

This episode initially followed the formula that Dr. Stone seemed to have mastered. Introduce a problem, and then create a solution with the help of everyone. However, the second half of the episode changed the tone completely. While generally speaking, introducing such a key character this late in the story is a sign of weak writing, this anime managed to do it perfectly.

In the previous episode, it felt like it was very convenient for Sai to exist. However, this episode took more time exploring his past, and his trauma, along with a more emotional side of Ryuusui that we’ve never seen before. I really like the way this episode fleshed out two characters in a single episode.

Anyway, what are your thoughts on this episode? Let us know in the comments.

Dr. Stone Science Future Part 3 is streaming on Crunchyroll.

Dr. Stone Science Future Part 3 Episode 4 Review: A Big Shift In POV