This particular device is fresh and edgy, and it fits the Firehouse Theatre like a glove. But it does have some disadvantages: There is the possibility of confusion as the mind attempts to impose conventional time on a structure of this kind. But more important, as this young man and woman romantically shadowbox with one another, there is little opportunity to generate any heat between the pair. The entire experiment would shrink into an intellectual curiosity if it were not for Brown’s talent as a songwriter. He blends accessible pop idioms with an aptitude for creating satisfying twists and turns during a song.

Any musical two-hander is inevitably going to turn into a competition of sorts. But “The Last Five Years” is not a fair contest. Both the story and the characterizations favor Jamie to an astonishing degree. He gets the cleverer songs, and it’s easier to track his story because it runs forward in time. Resnick exploits these advantages with a confident presence and the economical use of some blue-eyed soul. But the character’s real advantages are more insidious. Sure, he is narcissistic and has a wandering eye, but it’s not his fault that his wife is too insecure to deal with the fact that he is a hip writer-genius. The entire play is summed up in two lines:

“I will not fail so you can be comfortable, Cathy.”

“I will not lose because you can’t win.”

No wonder Jason Robert Brown’s ex-wife unleashed her lawyers on him for the original version of the script.

Unfortunately, the production exaggerates the inequality even further. While Resnick repeatedly engages the audience by moving closer to them and making steady eye contact, Director Isaac Butler generally keeps Brouillet upstage, preventing any intimacy with the audience. Too often, the amplified sound-levels drown out her voice. And she even sings sideways through an invisible Jamie to a blank wall on several occasions. Not one of these things is her fault, of course. During the quieter musical passages, when we’re allowed to hear her voice, her abundant talent and personality shine through. Like her character, she is shortchanged by a show that seems to say men and women are equal, but men are … well … cooler.

Looking back over this review, it appears more critical than I intended. The diabolical slyness of Brown’s lyrics is alone worth the price of admission. Count how many shades of meaning the word “fine” conveys during the show. It’s easy to see why he is so often compared to Sondheim. The performers are charming, and the lively three-piece ensemble (pianist and musical director Mark Andrist, guitarist Ryan Corbitt, and bassist Ryan Huett) fill the theater with an angst-scape of minor keys. There’s plenty of good stuff here.

But if you’re going to stage a battle between the sexes — even a poison pen letter to an ex — can’t we at least get the appearance of a fair fight? S