Unaware, you'd never guess Robert Lepage and Pedro Pires' "Triptych" was derived from a stage work, as there's nothing remotely theatrical left in this highly cinematic spinoff from longtime Canadian multimedia innovator LePage's nearly nine-hour live performance "Lipsynch." A fascinating three-part series of interlocking narratives pondering various forms of disability (among other things), the resulting work may be too uncategorizable to stir much commercial interest. But it merits extensive festival play, plus eventual attention from artscasters and niche home-format buyers.

The first segment is named after Michelle (Lise Castonguay), a middle-aged Quebec City woman released after a stint in a psychiatric institution -- on the condition that she continue her drug therapy, although it's immediately clear she can't be trusted on that score. She's most comfortable back at her old bookstore job, where she proves highly knowledgeable on just about any written subject. But her condition (presumably schizophrenia) has hardly gone away; she still has difficulty separating reality from the voices and images in her head. Among those concerned about her are sister Marie (Frederike Bedard), who at one point visits with her new husband, expat German psychotherapist Thomas (Hans Piesbergen). When Marie briefly leaves the other two alone, he gets a revealing earful of Michelle's feelings about being a pharmaceutical "guinea pig" for professionals like himself.

A slightly younger version of Thomas is the focus of the second part, which follows him during his earlier tenure as a Berlin-based neurological surgeon. He meets Marie after it's discovered that she has a brain tumor, for which he recommends surgery. This may be his last operation, however, since due to excessive drinking and stress -- his marriage to Rebecca Blankenship's opera singer Ada (Rebecca Blankenship) is crumbling -- his hands are growing too shaky for such precise work.

Even with the best possible outcome, that risky procedure will temporarily rob Marie of voice -- a terrifying prospect, as she's a Montreal jazz singer (though when we -- and Thomas -- hear her perform, it's in more of a Joplin-like bluesy rock style). The final sequence shows the many ways in which Marie is defined by her vocal abilities: dubbing character voices for children's cartoons, directing a church choir, etc. Her forced fresh start somehow provides a conduit for Thomas to leave his own old life and begin a new one.

Even within these sections, "Triptych" occasionally scrambles chronology and digresses into subplots and subthemes, with religion, medical science and music-making recurrent motifs. It's an artistic puzzle of the most engaging sort, with enough narrative shape (in contrast with the theatrical incarnation, according to some reports) to bind its more purely intellectual aspects.

The actors, most of them reprising their stage roles, are excellent, and the physically rangy production (shot in numerous locations over an unusually long period) is always aesthetically rich, despite some low-res passages in the digital lensing. In place of an original score, there's a very well-chosen selection of pre-existing classical pieces ranging from Mozart to Arvo Part.

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