Naka Shrine.
It was the ancestral ground worshipped by generations of the Uchiha Clan. The Uchiha had lived by the Naka River even before Konoha was founded, and Naka Shrine had a longer history than Konoha itself.
Tobirama was no stranger to this place. His understanding of the Uchiha Clan and the Sharingan even surpassed that of many Uchiha clansmen.
Many ancestral tablets stood in the main hall, bearing quite a few names he found familiar. Many places showed signs of repair, while the ancient tables, chairs, and altars carried the accumulated heritage of a great ninja clan.
Tobirama circled around to the back. After examining the floor for a moment, he lifted a stone slab, revealing a staircase leading underground.
The darkness below was utterly devoid of light, and there was no telling where it led. Tobirama looked thoughtful. He had learned from documents left behind by Orochimaru that a great secret lay hidden beneath the Uchiha's Naka Shrine.
He descended the stairs and lit the torches on the walls. It was a secret chamber, somewhat cramped, containing nothing but a stone tablet.
And that stone tablet looked entirely ordinary.
Tobirama studied the tablet for a long time and tested whether there was any Sealing Jutsu on it, but gained no useful results.
After remaining there for some time and confirming that he would find nothing, Tobirama chose to leave. Yet as soon as he stepped out of the underground chamber, he discovered that someone else had appeared in the main hall.
It was a black-haired boy holding a broom and sweeping the dust from the shrine. The fan crest of the Uchiha Clan was printed on his clothes, and judging by his forehead protector, he was about the age of someone who had just graduated from the Ninja