The Sonic Frontiers 'A Grave Mystery' puzzle unlocks once you collect the three Chaos Emeralds on Kronos Island and find enough of Amy's memories. A prompt will appear telling you to turn some tombstones in order to solve the island's mystery and keep progressing through the game's story—turns out, that's what the weird graveyard in the centre of the island is for.
That said, it's a little tricky to know which direction to turn the tombstones, especially as there are so many of them. In this A Grave Mystery puzzle guide, I'll walk you through which tombs to mess with, as well as the correct order and direction in which to turn them. I've also got you covered if you're struggling to figure out how Sonic Frontiers fast travel works.
A Grave Mystery requires you to rearrange four black tombstones so that a single beam of light can travel from the start point to the end. The only kicker is that when you move one tombstone, the other three also shift.
If you walk up to one of the four tombstones and interact with it, you'll be taken into a birds-eye view where you can rearrange all of them at once without having to run around. As you turn each, its beam of light will connect to other nearby graves. Here are the steps you need to take to connect the graves correctly and complete the puzzle:
This should complete the puzzle and unblock the waterfall, unbarring your progress so you can carry on to the next island.
