Dr. Stone season 4 episode 6: Luna's introduction reveals Senku and Dr. Xeno's true relationship

Heading into Dr. Stone season 4 episode 6, fans were expecting the installment to focus primarily on each Kingdom of Science’s respective assassination squads and their efforts. Officially released on Thursday, February 13, 2025, the installment did focus on Stanley Snyder’s group, but gave little attention to Tsukasa Shishio and co.

However, Dr. Stone season 4 episode 6 was still an incredibly exciting installment, with a major highlight of this excitement being the release’s final scenes. Here, fans discover the true nature of Senku Ishigami and Dr. Xeno’s relationship, setting up a climactic confrontation with emotional stakes for both.

Dr. Stone season 4 episode 6 confirms Senku and Xeno’s long-standing relationship

Brief episode recap

Expand Tweet

Dr. Stone season 4 episode 6 began with Gen Asagiri trying to come up with a way to warn Taiju and the others about the coming danger. However, the large woman who first appeared in the last issue was seemingly assigned to watch Gen, not giving him any opportunities to send a message out. Focus then shifted to Stanley Snyder, who was on his way to assassinate Taiju Oki and was accompanied by a girl with pink hair named Luna.

They discussed whether or not Gen was trustworthy, with Stanley making it clear he can’t be trusted. Two men named Carlos and Max then arrived with food and water, and were seemingly Luna’s voluntary servants based on the dialogue exchanged here. Stanley likewise specified that Luna couldn’t carry anything for fear of her body being marked, in turn seemingly ruining whatever plan Stanley had for her.

Dr. Stone season 4 episode 6 saw Stanley’s group take up shelter in a tree to scout Senku Ishigami’s Kingdom of Science. Stanley then set up a temperature/barometer and a wind vane, all tools which would help ensure accurate shots. Stanley then put his gun together, revealing his plan to snipe Taiju from a distance with a sniper rifle Dr. Xeno made. Gen was having this plan explained to him by Xeno at the same time, clearly concerned.

Luna's introduction brings with it a shocking side of Senku in Dr. Stone season 4 episode 6 (Image via TMS Entertainment))

When Stanley made his intent to kill Taiju clear, Luna was shocked at this and seemingly felt it was too cruel, but hid her true feelings when Stannley shot her a look. She then asked Stanley what her role in this plan was, prompting him to explain her role of getting on the ship and locating Taiju and signaling when she found him. The stripes on her dress likewise measured five inches across exactly, further helping Stanley gauge the distance and his aim.

Dr. Stone season 4 episode 6 saw Luna make contact with Senku’s group, with Taiju and Yuzuriha Ogawa being the first to rush towards and greet her. She said she escaped Xeno’s Kingdom of Science, with Ryusui Nanami already being suspicious and curious to see what Senku does. However, he immediately put the charm on when greeting her, making Luna blush and seemingly leaving her smitten with him.

Once on board, Kirisame helped to clean her up while she shot a brief signal back to Stanley indicating her success. Max and Carlos grew impatient, while Stanley excitedly waited for his opportunity. Nikki Hanada was immediately suspicious of Luna, who was being escorted by Minami Hokutozai around the ship. Senku then revealed he was also suspicious, but planned to use Luna to send Tsukasa’s group an encrypted message about Xeno.

Expand Tweet

Dr. Stone season 4 episode 6 then shifted focus to Tsukasa’s group, who decided to start their mission by gathering as much intel as quickly as possible. Minami was then shown sending out messages of treaties and peace negotiations to Xeno’s camp, which she recognized was likely a futile effort. Luna, meanwhile, was now freely walking around the deck of the Perseus with Kirisame escorting in her attempt to locate and identify “Dr.” Taiju.

Ironically, her image of what Taiju would be was essentially what Senku is, also expressing concern that he’d be just her type likewise. She eventually identified Taiju after Yuzuriha called him by his name, ruining Luna’s mental image of him likewise. As she mused on how to identify Taiju to Stanley, Senku turned the charm on and asked Luna to tell her everything she knew about Xeno.

However, he was interrupted by Ryusui and François, with both of them urging him to let her handle “interrogating” her by making use of their on-ship bar and restaurant. They decided to start with making ice cream from scratch, with Senku assisting by synthesizing vanilla extract. Dr. Stone season 4 episode 6 saw Luna catch a glimpse of this science experiment with Senku at the helm, clearly growing suspicious at what was going on.

Like Luna for Senku, Gen may be the one to help Dr. Xeno realize he's more familiar with his enemy than he thinks in Dr. Stone season 4 episode 6 (Image via TMS Entertainment)

Hilariously, Luna still didn’t recognize that Senku was the scientist and Taiju was the brawns, even when he was the one who manually mixed the ice cream. As she went to try and identify Taiju to Stanley, Nikki caught her and escorted her to Senku instead, who gave her and several others onboard the freshly made ice cream. Luna was shocked and asked Senku how he made it without vanilla, prompting him to lecture about science and how humanity passes it on.

Dr. Stone season 4 episode 6 saw Luna conflicted with her feelings, thinking she was supposed to fall for the true genius scientist, Dr. Taiju. She quoted Dr. Xeno’s use of the word “elegant” to compliment Senku’s process, prompting him to seemingly realize who he was. The episode likewise ended with a flashback showing a younger Senku being mentored by Xeno, with Senku confirming as much himself in the final scenes.

Final thoughts

Expand Tweet

With the latest episode ending with a major revelation on the coming battle’s context, fans are excited to see where the series heads next. Likewise, it’s expected that Xeno will soon make a similar discovery, either via Gen slipping up and mentioning Senku or via Stanley reporting in and describing him physically. In any case, fans can expect this to mark a heightening of tension, stakes, and action for the episodes to come.