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At the starting coordinates you're at the main entrance to the castle. If the gates are open you may enter, follow the road up the hill, and visit the public areas, but you won't be allowed to enter the castle and meet the queen. No one will help you there to reach the queen and the secret letter won't be delivered. Ever. You must think of other ways to the castle and to the queen.
Desperately you decide not to go up the hill but walk east instead and come to a tavern. Unfortunately, no one is willing to help you there. So you don't stay for a drink but keep on walking.
Suddenly, after walking further a dog gang attacks you, so you run from them without looking behind, pass the road, and run down to a small river. Now you can look around, you don't see the dogs, so you luckily escaped. This was tough, you've almost forgotten your mission.
At the river you see some stairs, you sit on one of them for the rest and realize that there is a secret path under the stairs. This might be a secret entrance to the castle! But you need to wade. You put your rain boots on (luckily you are always prepared) and wade a few steps. There you see a box with a sign of the royal post — a broken arrow. No no, it's in no way related to the lightning or anything dangerous — it's the sign of the royal post which stops the fights.
Here you may leave your secret letter for delivering to the queen. Your mission is completed, but you need to sign the guestbook otherwise your log will be deleted and no one will ever believe you've succeeded.
The royal post may also be used for sending goods which include their tracking codes (TBs and GCs whatever that mean).
As usual, you will find a stamp in the post box, it's not a trading item and must stay for other postmen and postwomen to stamp their letters.