Swamped

There's one obvious way to get an investigation started: let the Marshguards capture you. It shouldn't even be that hard, since they seem to have an interest in you.

And Nathan mentioned that lookouts are often the enemy's first target. That might be a good way to get yourself caught.

It shouldn't even be that dangerous, since they'll release you after the next rain.

But... well, you're still a trainee, and you don't even have an official status right now. Still, it can't hurt to say that you're interested in being a lookout.

You've got time to work out the details later. For now, you have to send this letter... and it occurs to you that you aren't sure how exactly that works, so you ask Mary.

"Oh, right, you're new, I've got to remember you don't know about everything yet. I'll take you to the Roost."

You don't know what she means by that, but you suppose it will be clear enough once you arrive. So you follow Mary up several flights of stairs, finally reaching a tall ladder against a side wall.

"Oh. You might not be able to get up that," she says, a little embarrassed.

"Well, I'll give it a try," you say. "Could always do with more climbing practice. Just stay at the bottom in case I need help."

You carefully attempt to climb the ladder. It's a bit awkward, but not as bad as the climbing wall was with both hands. After a while, you get the hang of it, and you emerge in a room filled with crows, many of them in cages. A knight waves at you, as Mary scrambles up the ladder behind you.

"Oh my, must have been tough getting in here? Terribly sorry. I'll ask the Captain if we can do something to make it easier for you next time. Oh, wait, we haven't met, have we? I'm John Two Hundred Twenty-Sixth, but generally they call me the Postmaster."

"Not John Postmaster?"

He shrugs.

"Nope. Maybe because it's a new position. Really been a great thing for morale, though. You have a letter?"

"Oh, yes."

"Right. Well, where's it going?"

You tell him the name of your hometown, explaining that it's near the border with Kroska.

"Right, right. Dorvin's gonna be the closest outpost to there. So let me just mark this letter... need the recipient's name, and any other details to help them narrow down where to take it on the other side."

A brief interrogation later, he walks over to a cage. You suppose the writing on it says "Dorvin", though you can't really tell. He takes the crow out and ties the letter to its leg, then walks over to a window shutter and opens it.

The crow flies off, taking your letter with it.

"And there you go! It'll stop at the roost in Dorvin, and from there someone local will take it out to Henry. Should only take a couple of days. I'll let you know if a reply arrives. Oh, are you going to need help getting down?"

You probably are, now that he mentions it. Enough trouble that you might want to take the time to ask him some questions before you make the effort.