Some Octopath Traveler 2 side stories are actually part of a continuing chain of events, and the “Proof of Guilt” one in Timberrain is a good example. Outside the courthouse is a guard named Meylan. Talk to him during the day, and you’ll get a “Proof of Innocence” quest. Speak to him at night, and “Proof of Guilt” triggers. However, while one is as easy as bringing a person over, the other involves searching for clues to get the missing Azure Sun Sword.
After talking to Meylan at night to get the quest and learn he needs the Azure Sun Sword evidence, head south. You’ll see a Remorseful Old Man standing by the fence near the tavern. You’ll need to have someone like Osvald Scrutinize him or Hikari bribe him. I recommend not going with Scrutinize, as it is a bit of a high threshold. (My level 30s Osvald had 32% odds of succeeding at the time.)
The Remorseful Old Man is the father of the defendant. He hid the Azure Sun Sword. You’ll find it to the left of the Timberrain Inn as a hidden item. Once you get it, head back to Meylan at night. Give him the sword to complete the “Proof of Guilt” Octopath Traveler 2 side story. You’ll get 12,000 leaves and a Critical Nut (L). This will also open up the final part in the trilogy, “Proof of Justice.”
Octopath Traveler 2 is available for the Switch, PS4, PS5, and PC. A demo is available.