The geocache is not at the posted coordinates. To find it, you must complete the Haunted Franklin Adventure Lab and get the clues.
Once you have completed the 5 locations of the Adventure Lab, you will have the information necessary to get the final coordinates for this bonus (mystery) geocache.
At the completion of each lab stage write down the answer for each stop to get the final coordinates:
N 39 28.ABC W 86 3.CDE