Blackfriars Theatre caps off an exceptional first season in its new East Main Street space with the similarly exceptional "A New Brain." Another ambitious undertaking by the company, the musical is at times hilarious, deeply moving, and almost relentlessly entertaining - so entertaining that you'll hardly mind the resulting minor existential crisis.

"A New Brain" tells the story of Gordon, a talented but frustrated would-be Broadway composer forced to make a living writing what he considers inconsequential ditties for a children's TV show. Gordon is having lunch with his agent, justifying his latest blown deadline, when he experiences a strange sensation and ends up face down in a plate of baked ziti. At the hospital, Gordon learns that he has a serious brain abnormality, one that requires a surgery that could either fix him, or leave him paralyzed or dead.

Faced with impending mortality at a fairly young age, Gordon begins questioning the decisions he's made in his life - specifically the fact that he never wrote the music he wanted to, and how his pervading cynicism has unintentionally affected all of his relationships. Meanwhile, his mother, boyfriend, and friends try to come to grips with Gordon's situation and his increasingly grim prognosis. And a wise, sassy homeless woman somehow ties it all together.

While "A New Brain" is technically a musical, there are times that it actually feels more like an opera - a thoroughly modern, zippy opera. Almost every line in the play is sung, right down to the specials of the day at a sidewalk caf�. Most of the characters have their own musical theme, and the music doesn't stop for its nearly two-hour, intermission-less run. (Actually, the play itself doesn't stop, thanks to director John Haldoupis' brisk staging and brilliant, transforming set.)

A strong ensemble is required to pull off that theatrical marathon, and Blackfriars has found 11 actors up to the challenge. Sure, there are a few wrinkles - on opening night the difficult rhythms of the first few multi-character numbers weren't synching up, and the piano sometimes drowned out a few of the actors. But by the first big group number, "Heart and Music," things came together nicely.

Almost every character in the show gets a chance to shine, even those with smaller parts. Nicholas D. Rogers has several nice moments as the self-pitying fat nurse, who will be nice to you, unlike "those other bitches." Dawn M. Sargent evokes a bit of Janis Joplin in her role as Homeless Lady. She's completely tangential for most of the play, coming in for group numbers and then getting a few bluesy, ballsy solos of her own, but oddly charming in her fatalism when she finally engages with the other cast members.

Danny Hoskins is a hoot whenever he zips in on a scooter as Mr. Bungee, the frog-clad host of the TV show Gordon writes for. Hoskins - who is affiliated with Rochester Children's Theatre - must have had fun playing the darker side of kids entertainment, a screeching egomaniac who torments the lead character both in hallucinations and in real life, but who ultimately fulfills the role of every good children's TV show host: to impart an important life lesson.

I've seen Matt Tappon in several local productions and have always been impressed by his strong voice. He still surprised me in his performance as Gordon, fully immersed in the role from beginning to end. The play requires Gordon to tackle some complicated emotions, from guilt to regret to elation, and Tappon executes all of it flawlessly.

Jason Mincer plays Gordon's boyfriend, Roger, and he is introduced while singing his big number, "I'd Rather Be Sailing." Mincer's beautiful tenor voice was so moving that the woman in the audience behind me burst into tears, and that is not an exaggeration.

Sarah Peters plays Gordon's mother, Mimi. Peters is a member of the Village Idiots improv comedy troupe, and those chops are put to good use in this role, but they're balanced by Peters' impressive dramatic abilities. The scene where the relentlessly chipper Mimi goes to clean Gordon's apartment and finally lets down her brave face is gripping - her grief and rage are nearly palpable. Peters is also sensational in her music numbers, and probably has the best songs in the show. She's a real dynamo.

As for that existential crisis, I imagine it's hard for anyone - but especially a cynical writer who makes a living critiquing other people's creativity - to watch this show and not see a giant, flashing sign reading, "You Are Wasting Your Life." Why aren't you doing what you want to do? Is your cynical outlook subtly poisoning all of the positive aspects of your life? But there is some comfort in knowing that the show is mostly autobiographical, and that playwright William Finn set about writing his music after experiencing a medical emergency similar to Gordon's. That was his wake-up call. Perhaps "A New Brain" can be yours.

"A New Brain"

Through May 22

Blackfriars Theatre, 795 E Main St.

454-1260, blackfriars.org | $15-$27