Darius orders a search of the archives in Babylon.
But it's in a search of the archives in Ecbatana, the capital of Media, where they discover that Cyrus really did decree the rebuilding of Israel's temple (along with some stipulations about its size and about returning the vessels).
So Darius sends a letter ordering Tattenai and the other officials in the province to let the people of Judah go on with rebuilding.
He tells them to pay the people of Judah to rebuild the temple, covering the cost from the province's treasury, and to also supply all the young bulls, rams, and sheep for offerings, and all the wheat, salt, wine, and oil the priests require.
Darius says that if anyone alters the edict, they'll be impaled on their own roof beam and their house will be turned into a dunghill.
Darius also asks God to overthrow any kings or peoples who attack and try to disrupt the rebuilding.
Tattenai and the other officials back off after the threat from Darius, and the elders keep building and prospering. Zechariah and Haggai keep encouraging the people through their prophecies.
They finish the temple in the sixth year of Darius' reign, thanks to God and the decrees from the Persian Emperors. Even Artaxerses is OK with it.
The people of Israel and the priests and Levites all celebrate, offering mass quantities of bulls and rams and lambs, along with twelve male goats symbolizing the twelve tribes of Israel.
They also celebrate Passover. The priests and Levites purify themselves, and everyone eats the Passover lamb.
Not only the people of Israel eat the lamb, but others who have separated and cleansed themselves from the nations' impurities get a turn at the buffet.
The people are overjoyed that God inclined the heart of the king to let them build.