Charm him

You cast a Charm Person spell, and the lazy guard stands up, reaching for his sword, but it's too late.
His eyes are covered in a pink energy, and he smiles at you.

"Hey friend" you said gently "You look like an intelligent man who knows things. Tell me… I'm looking for a magic stone, something powerful and I know that it's in the city. Can you give me any information about that?"

He's worried and whispers something in your ear, "The blacksmith is working on something about a stone from the Lord of the town. Strange stuff. But the blacksmith is a dangerous man, be careful and don’t mention I told you this."

You can go to the blacksmith or walk inside the barracks to speak with the captain. You notice a big wooden door at the end of a passage.