[plot description by original author]
The Hook, Line and Sinker format appeared in SHADIS magazine:Hook: The current location or situation of the party.
Line: The situation which introduces the side-adventure.
Sinker: The twist, or what is unknown to the party, and the result.
HOOK: The party is in a dungeon that was formerly part of the castle of an ancient king.
LINE: In a certain room of the dungeon, the party comes across a parchment in the ancient tongue of the area, before the Beast Wars (or similar war with evil monsters) levelled the castle and wiped out its inhabitants. When deciphered with language knowledge or a spell, the letter appears to be from the chamberlain (head servant) of the castle to his son, explaining where he hid his personal savings. These may be much smaller than the Royal Treasure Vault, but still worth looking for as a side-adventure!
SINKER: Nothing comes easily, especially when dealing with ancient and poorly understood writings. The chamberlain said he had a personal treasure vault fitted with a lock that could only be opened by a magical medallion. He split the medallion into three pieces and chose to explain where he hid the pieces in a cryptic poem:
The first piece, with necklace, I hid in plain sight,In this example the piece with necklace chain was cleverly concealed in the chain-work of the chandelier! The second piece was up a chimney in a room which no longer has wine casks. And the third is indeed concealed as part of a mural, with the exposed surfaces painted to better hide the glint of metal. The pieces magically jump together and assemble to form a medallion with 3 evenly spaced square notches cut from the circular shape. These notches fit grooves in a recessed hole in the wall with bizarre metal rods resembling a bundle of spaghetti. If the medallion is pushed into this assemblage of metal rod ends, the face on the medallion pushes in the appropriate rods by the exact amount required for each rod to open the lock. Note that the poem alludes to some sort of proximity trap.
But without the two others it won't work out right.
The second I hid in a room full of wines,
You will have to endure some precipitous climbs.
The third piece I put in a face in the wall,
You must thrice tap a smile in the Great Dungeon Hall.
They'll assemble by magic, with loud ringing clack;
Then you press to the lock--be sure to step back!
Endless variations are possible for more than one ancient castle official! Maybe the current inhabitants of the dungeon have "remodelled." So references to "the third door on the left" are meaningless, or the letter-writer talked in terms familiar to castle inhabitants but which are meaningless to the explorers of the ruins.