What should I do with that letter. It says that "the crown is in danger". But there is no clues. Thanks in advance.
<SPOILER> It is required sometime later in Tarant as part of the Arcanum X files quest (starts with a message delivery quest for a half-orc near Sammy White). </SPOILER> IMHO, this was one of the more interesting side quests - one that really don't give you a fancy item, but draws you into the gameworld.