WARNING: The following article contains spoilers for Season 1, Episode 16 of Dr. Stone, "A Tale For The Ages."
For the past few episodes, Dr. Stone has been teasing a big mystery pertaining to Senku's surname and how it links to Ruri and her village. Now, in Episode 16, we know exactly what ties Senku to a community that exists thousands of years in the future: his father, Byakuya Ishigami, the man Ishigami Village was named after.
The other nagging question is how Ruri, a teenage girl, could possibly know Senku or his father's names -- men born well before her time. As Ruri explains, her role as priestess has less to do with magic and more with the preservation of history; specifically, the folklore handed down through her family, generation after generation. These stories are collectively known as The Hundred Tales, and the 100th, which she recites in the episode to Senku and others, is called "Senku Ishigami." This is why she recognized and knew the name of the spiky-haired scientist when he arrived in the village.
Back in Senku's original time period, Byakuya was desperate to become an astronaut, but he kept failing one of the physical challenges: to swim in water with your clothes on. After confessing this to a young Senku, the aspiring genius got to work creating a suit that would help his father get better at this particular test, and like everything Senku puts his mind to, it worked. By the time Senku reached high-school age, Byakuya had become a fully-qualified astronaut and embarked on his first mission aboard the International Space Station.
Among the select few on board is an even more unlikely candidate than Senku's eccentric dad: a pop star called Lillian whose sole purpose seems to be delivering live space concerts that are broadcast around the world. She and Byukuya form a close friendship, as do the others on the mission, but their peaceful work is interrupted by the mysterious event that encased every human on Earth in stone in the anime's first episode. From space, a green glow folds around the planet before suddenly disappearing.
The team frantically try to communicate with NASA. When they get no response, they tap into cameras using the Internet. This reveals the horrifying truth -- a sea of frozen, hardened bodies. Slowly, the astronauts realize they're the only humans left unaffected. Rather than wallow in anguish, Byakuya demonstrates some of the gritty resolve we've seen from his son. He states that the group has no choice but to return home to attempt to save the 7 billion petrified lives.
Already we can start to fit some of the pieces together ourselves from this information. Senku commented at the start of the episode that Ruri and Kohaku looked oddly "foreign" considering Ishigami Village is in what was once Japan. Lillian is the spitting image of these two, meaning she has to be their ancestor. As evidenced by the still-petrified stone bodies littering the Stone World, Byakuya and the others' plan probably didn't succeed, leading them to instead repopulate the planet in the hopes of kickstarting a new civilization.
It's possible, too, that Byakuya found and moved Senku's frozen body into the sheltered environment he woke up in, and ensured that the stories of his time were mythologized by Ishigami Village's culture in case his son was ever restored and needed to know what happened to him.
Obviously, this lends Senku's recent ascension to Village Chief a sense of destiny. The past and present are all starting to connect in Dr. Stone, and it'll be interesting to see what Senku does with his newly acquired knowledge.
New episodes of Dr. Stone air every Saturday night as part of Adult Swim's Toonami block and are available on Crunchyroll.