Dan Moses, Kate Kilbane, and Julia Brothers Photo by Julie Schuchard

Local musicians The Kilbanes have mined this story (part of Ovid's Metamorphoses) to create a rock opera that, while softening somewhat the savagery of the original (no boiled babies!), retains a tragic mystery that is reflected in a haunting and powerfully rhythmic cycle of songs. Entitled Weightless, it is currently playing at Z Space in San Francisco, one of the City's most interesting and energizing theatrical spaces.

In the almost-cavernous warehouse space, the set (by designer Angrette McCloskey) creates the feeling of going to an arena rock show where you've scored floor seating. A large raised stage is flanked by (sadly very uncomfortable) amphitheater-like seating and surrounded by several poles topped with arrays of lighting instruments. It is both operatic and intimate. Upstage are four large gourd-like elements that feel like a cross between bowling pins and the pods from which Spinal Tap failed to emerge in This is Spinal Tap. A wide ramp angles down from the stage front to the floor, creating a space where much of the action should—but fails to—take place.

Herein lies the biggest problem with Weightless. Despite the engaging, powerful, and oftentimes touching score, Weightless is more of a song cycle than a true opera (rock or otherwise) because of a paucity of dramatic action. The story of two sisters who are separated when one marries a king has theatrical potential aplenty, but director Becca Wolf has chosen to tell us the story rather than show it to us. There is plenty of story here, and plenty of space in which to tell it, but far too often the performers are held static, undercutting the inherent drama and emotion of sisters bound by love, but separated by lust.

There is still a tremendously powerful show being presented here. The band (authors Kate Kilbane and Dan Moses, assisted by singer Lila Blue, drummer Dan Harris, and guitarist Josh Pollock, who sings the role of Tereus) is marvelous, filling Z Space with sounds that range from powerful angry ballads to heartsick, tragic blues like "Nightingale," hauntingly performed by Lila Blue. And when Josh Pollock sets down his guitar and joins Dan Harris, pounding a tom-tom with vicious beats from timpani mallets, the rhythms take on a primal feel that is most compelling.

The performers are mostly excellent. Kate Kilbane's passion is evident in both her vocal performance and the imaginative and powerful bass lines she creates. Lila Blue is appropriately delicate and wounded as Philomela, but her voice can be a little thin when she needs to belt. Julia Brothers brings a wonderfully snarky appeal to her role as God, but adding a touch of menace to some of her line readings would add a level of dimension and gravitas to her character.

This world premiere has been five years in the making (first appearing in a different form at the 2012 SF Fringe Festival), but would benefit in its next iteration from a more theatrical, dramatic staging, perhaps confining the band to playing the score, and allowing actors/singers to concentrate on the drama and the interactions with their fellow performers. Still, Weightless has an undeniable power and is well worth seeing, even in this flawed but fascinating first full incarnation.

Weightless, through March 18, 2018, at Z Space, 450 Florida Street, San Francisco CA. Shows are Wednesdays at 7:00p.m., Thursdays, Fridays and Saturdays at 8:00 p.m., and Sundays at 2:00 p.m. Tickets are $10-$125 and are available online at www.ZSpace.org. (I recommend general admission tickets, as these mostly have backs and, while farther from the stage, have a direct view.)