Light our Shadows

This time they'd done it. As all powerful co kage's there weren't any foes that husbands Sasuke and Naruto couldn't bring down. They were the strongest ninja alive. Their unity only made them stronger. No one could take them down in their current states. There was peace between nations. Aside from the random Kaguya worshipper who wanted to try to free her now and again. Which is why they really should have been ready when their foe whipped out a time travel jutsu and declared he'd kill their childhood selves.

Or

The fic where Naruto and Sasuke have to travel back in time and guard their academy selves. It should have been simple. Easy. Except it wasn't.