This route is on the East Face of the Third Pinnacle (facing the Amphitheater) and ascends a left facing dihedral located near the center of the face. It is not to be confused with Halls of Poison Ivy which is located on the Fourth Pinnacle...
Climb the left face of the dihedral passing a ledge with poison ivy on the left and a roof band also on the left. When the dihedral runs out you will reach a large ledge. Traverse left to the base of the 15 foot summit block until you find a fist crack. Climb the crack to the top.
As a variation you can traverse left after the poison ivy ledge and crank the roof at any of two wide cracks then continue up to the summit block. This variation is probably in the 5.6 range.
Descent: Downclimb the fist crack off the summit block and scramble West to hiking territory
Standard Flatiron rack