Welcome to the Story Walk, bonus cache. Do not go to the posted coordinates, there is nothing there, and there may be water. You will need to complete the Story Walk Adventure Lab to obtain the final coordinates for this hide.
This is a high muggle area, so put on your stealth coats when going for this hide. Bring you own pen, as there isn't one in the hide.
Most of all, enjoy your walk in a beautiful park. There is so much to do here.