The episode begins with Senku and the Kingdom of Science continuing their sea voyage aboard the Perseus, heading toward America. The crew is divided on the best route: Ryusui, as captain, favors a direct 70-day path, while Senku advocates for a shorter 40-day route that demands twice the crew's effort but is necessary to reach America in time to harvest corn for producing revival fluid. Gen sides with Ryusui to avoid heavy labor, and Kohaku supports Senku. To resolve the disagreement, they decide to settle the matter with a high-stakes poker game, emphasizing fairness and camaraderie among the crew.

As the poker game unfolds, the crew's morale and dynamics are highlighted. Gen and Francois focus on maintaining the crew's happiness and efficiency during the voyage, while Tsukasa leads the warrior team in rigorous training sessions to prepare everyone for the challenges ahead. The episode shows the crew's daily routines and interactions, emphasizing teamwork and the balance between science and strength needed for their expedition.

During the journey, Chrome uses a sunstone device to help the Perseus stay on course through stormy weather. This scientific tool proves useful but does not create dramatic tension, as the ship's safe arrival seems assured. The episode's pacing slows down, focusing more on character moments and the calm before the upcoming challenges rather than intense action or scientific breakthroughs.

Upon arrival in America, the crew disembarks and begins to explore the new environment. They encounter mysterious glowing letters in the sky, which initially frighten the crew, who suspect supernatural causes. Senku and Zeno quickly deduce that the glowing letters are actually phosphorescent paint on kites, dispelling the fear of a supernatural threat.

The next morning, Senku and the others meet the person responsible for the glowing kite messages--a girl with poor eyesight named Chelsea. She had been unpetrified about a year ago but got lost because she missed Zeno's signs. Senku gives her glasses, which greatly improve her vision and spirits. Chelsea is thrilled and eager to join the Kingdom of Science's efforts.

The episode ends with the crew settling into their new surroundings in America, preparing for the scientific discoveries and challenges that lie ahead. The tone is calm and reflective, setting the stage for the more intense plot developments expected in subsequent episodes.

The ending of Dr. Stone Season 4, Episode 2 "SCIENCE JOURNEY" shows the crew aboard the ship Perseus successfully arriving on the American continent as planned, with no major incidents during the voyage. The episode closes with Homura confirming the ship's safe landfall, setting the stage for the next phase of their scientific adventure.

Expanding on this ending scene by scene:

The episode primarily focuses on the journey of the Perseus across the ocean. Early on, Chrome uses a sunstone device to help navigate through stormy weather, ensuring the ship stays on course. Although this scientific tool is interesting, the results are relatively uneventful, and the ship's progress is steady but without dramatic tension.

As the voyage continues, the crew experiences a calm period, which serves as a breather from the high-energy scientific experiments typical of the series. This slower pace allows for some character moments and a glimpse of normalcy before the upcoming challenges. The episode emphasizes the crew's teamwork and the reliability of their scientific methods, but it lacks major plot developments or cliffhangers.

Towards the end, the Perseus reaches its destination on the American continent. Homura, a key crew member, confirms the ship has made landfall safely. This moment marks the conclusion of the episode and the successful completion of the journey segment. The episode ends on this note without introducing new conflicts or villains, leaving the audience anticipating the next episode's developments.

Regarding the main characters involved at the end:

• Senku Ishigami remains the central figure, leading the scientific mission with his characteristic intelligence and determination. He is aboard the Perseus and is poised to continue his quest to rebuild civilization using science.

• Chrome plays a crucial role in navigation, successfully employing the sunstone to guide the ship through difficult weather.

• Homura confirms the safe arrival, indicating her active participation in the mission.

No major character deaths or dramatic changes occur in this episode's ending; all main participants arrive safely and ready to face the next stage of their journey.

In summary, the episode ends with a calm but successful arrival of the Perseus on the American continent, highlighting the crew's scientific ingenuity and teamwork, while setting up anticipation for future scientific discoveries and challenges.

Based on available sources, there is no evidence of a post-credit scene in Dr. STONE, season 4 ("Science Future"), episode 2 ("SCIENCE JOURNEY") produced in 2025. The episode focuses on the ongoing sea voyage of the Perseus, with key scenes including a bar sequence where Francois crafts personalized drinks for the crew, Matsukaze revealing more about his lord and prompting the revival of former enemies for training, and Chrome devising a navigation method for stormy weather. Reviews and summaries do not mention any additional content after the credits, and no fan reactions or episode guides reference a post-credit scene.

Therefore, it can be concluded that "SCIENCE JOURNEY" does not feature a post-credit scene. The episode's narrative concludes with the crew continuing their journey, preparing for the challenges ahead, and no extra scene is presented after the credits roll.

The flashback reveals Senku's childhood attempt to build a rocket with Taiju and how a young Xeno, then 20 years old, secretly helped Senku by providing instructions and materials through Senku's father Byakuya's government credit card. This establishes Xeno's early connection to Senku and his bitterness from repeated project rejections at NASA, setting up his later antagonistic stance in the stone world scenario.

During the 40-day journey to North America aboard the Perseus, the group faces stormy weather, which Chrome helps navigate by devising a method using sunstone. The episode also shows the group training and reviving former enemies like Hyoga, Moz, and Homura to prepare for upcoming conflicts, highlighting character growth and teamwork.

The group discovers corn grains floating down a river, which is unusual. Senku sets up a light trap and finds moths that feed on corn and others that feed on fabrics--species that should have declined after humanity's petrification 4,000 years ago. This odd presence suggests something unnatural, leading Senku and Tsukasa to sense a bloodthirsty enemy watching them, culminating in an ambush with machine gun fire.

Matsukaze reveals more about his lord and their backstory, which prompts the group to revive some of their former enemies to help him train. This development adds depth to Matsukaze's character and sets up new dynamics and challenges for the group as they prepare for future conflicts.

Episode 2 ends on a triumphant note as the group seemingly arrives in America after their journey. Despite some pacing issues early on, the episode balances this with strong character moments and a significant flashback, setting the stage for the next arc of the story to begin with the group's arrival in the new territory.

The TV show Dr. STONE, including Season 4 titled "Science Future," Episode 2 "SCIENCE JOURNEY," is generally considered family friendly with mild content but is rated TV-14 in the United States and PG12 or 13+ in several other countries, indicating it is suitable for teens and older children with parental guidance.

Potentially objectionable or upsetting aspects for children or sensitive viewers include:

• Mild violence and intense scenes: Some scenes may be emotionally intense or mildly frightening, consistent with action and conflict typical in adventure anime. For example, earlier seasons have moments of character death that can be emotional, though no extreme gore is present.
• Mild profanity: Occasional use of mild swear words such as "shit," "dick," and "crap" alongside lighter terms like "ass".
• Mild references to alcohol and medicine: Some depiction of alcohol use and antibiotics, but no drug abuse.
• Scientific and technical themes: The show heavily features scientific concepts and inventions, which are presented in an educational and often comedic way, unlikely to be upsetting but possibly complex for very young children.

No explicit sexual content or strong language is noted for Season 4, and the violence is mild without graphic gore. Overall, Dr. STONE Season 4 Episode 2 is suitable for older children and teens with some parental discretion advised for younger or sensitive viewers due to mild language and emotional intensity.