The book describes it as the "face left of Man and Superman". Climb through a series of obvious features until you come to the blank section. Figure a way through it, then it's easier climbing to the top.
The book's description is limited, so I wasn't sure how close you can get to the Man and Superman arete on this climb. The sequence we figured out used holds that were just left of the arete, and it made it feel a easier than 12, so I figure we were probably off route. It was a fun problem either way.