Darius was not the type of king to take hasty sides in petty provincial disputes, so he instructed his bureaucrats to search the archives and sort out the matter. When they reported that Cyrus had issued a decree permitting the Jews to rebuild the Temple, Darius wrote back to the governor, telling him to leave the Jews alone. The work was legal, and should be supported with animals for the daily sacrifices. Furthermore, if anyone tried to hinder the construction, that person should be promptly impaled upon a stud from his house and his house razed and turned into a latrine.
After that, construction went on swimmingly and the Temple was finished in another six years. The Jews threw a massive barbecue in celebration, and Passover was super awesome that year too.