One of the great pleasures of the Philly Fringe is discovering buildings (now venues) you probably never knew before. There is much to praise in New Paradise Labs' provocative Planetary Enzyme Blues, but let's start here: The Cathedral, at 42nd and Spruce streets, is a gothic wonder located in our own backyard. Who knew?

Into this hushed, reverent world, Whit MacLaughlin (he conceived, wrote and directed PEB) has inserted a second one. His program notes speak of the influence on this piece of various historic back-to-nature movements in Philadelphia, but I suspect MacLaughlin is being sly. The visual environment of PEB is a desolate urban encampment; there's part of what might be a bunker, as well as a geodesic dome-shaped tent. There is also a radio tower, encircled by a halo of light. Broadcast fragments emerge from static, and we hear about violence — in Alabama and also in Vietnam.

Where are we? It's truly the end of a world, friends — where the '60s meet the '70s.

PEB muses on the youth movement as it confronts the death of innocence — and idealism becomes self-centeredness. We follow a short period in the lives of six coming-of-age Philadelphians (three men, three women). They couple and uncouple, take drugs, explore their options. Guiding the audience through this journey is a disembodied female narrator. Her voice is soothing yet authoritative, equal parts psychoanalyst and stewardess.

Along the way, PEB refers to, and seems to draw inspiration from, several movies. Easy Rider brings us disaffected outsiders. Barbarella introduces cheeky sex. From 2001: A Space Odyssey comes an array of baby images of various shapes and sizes, and a sense of awesome, unknowable eternity.

Everything about PEB is simultaneously intriguing and (deliberately) frustrating, at least to those who seek reassurance in linear narrative. You won't find it here. The show favors visual éclat (considerable) over cohesiveness (minimal).

Like many Live Arts pieces, this isn't for everybody, and will probably be self-recommending to a core following. (Also as with many Live Arts events, the space is not air-conditioned — wear as little clothing as you possibly can.)

For what it's worth, I found much of it quite hypnotic and fascinating, and was drawn into the clever narrative, full of knowing homilies like, "Fun is the holy grail of youth." On the other hand, 70 minutes is a lot of it. On yet another hand, the final section — sardonic, mournful, visually astonishing — makes it all worthwhile.

Put it another way — five days later, I'm still haunted by images from PEB, and that's really saying something.

Planetary Enzyme Blues Through Sept. 17, New Paradise Labs/Live Arts Festival, The Cathedral (St. Andrew's Chapel), 4201 Spruce St., 215-413-1318 or www.livearts-fringe.org.