'John & Jen' an uneven mix of music and cliché

John & Jen

, a little musical about a brother and sister, and then a mother and son, is a seesaw. It opens with a halting script in Act II Playhouse's sweet and strongly performed production, then gets richer and better - good enough for the first act about two siblings to stand alone.

When the second act begins, about the sister and her son, we're down again, not sure where we're heading, plus we seem to be hearing what we've already heard. Then, in another tune or two - the show is mostly sung - it begins to parallel Act I in a curious, smart way, and we're back on the ascent. Finally, it falls again, from the edge of realistic mother-son drama into a touchy-feely swamp, presumably sending us out with a sudden spike of warmth, a sort of fast-speed "Kumbaya."

John & Jen is the circle of life without the royal lions: Get yourself born, grow up, fly the nest, grow old, face the inevitable finale. Were I cynical, I'd call it an Act II Playhouse specialty, the third musical of its sort on the Ambler stage in less than a year. But that's an incomplete picture; next up is Shakespeare.

Still, John & Jen bubbles from a modern musical-theater formula the stage company has appropriated: Paint life in wide strokes, keep it all simple, have someone (preferably portraying a child) sing about how she's going to fly (preferably like an eagle). Toss in basic theatrical herbs: guilt, remorse, obsession.

John & Jen has all this, but it also seriously considers abusive parents and family rifts, set against the life span of the baby boom. And it conveys the pain of being perceived as wrong no matter what you do, from the viewpoints of a child and an adult. Tom Greenwald and Andrew Lippa wrote the show's book; Lippa (currently on Broadway with The Addams Family) composed the generic score, with its repetitive, predictable piano counterpoint that runs through so many musicals these days. Greenwald wrote the lyrics, some strong, some weak.

The show has its genuinely worthwhile moments, but the high quality of Act II's production is uniform throughout. Megan Nicole O'Brien's staging is active without being overdone, a particular feat when the show's two A-1 performers, Sarah Gliko and Michael Philip O'Brien, play cute little children - a risky proposition for a director and an actor. (The O'Briens are cofounders of Philadelphia's 11th Hour Theatre Company.)

The two performers - blessed with emotive singing voices and commanding stage presences - move with style around Dirk Durossette's inventive, minimalist set, its shelves holding the knickknacks of home life. Among them is a bowl with two constantly moving goldfish that seem to dance to the well-performed accompaniment of the backup trio.

Playing at Act II Playhouse, 56 E. Butler Ave., Ambler, through Oct. 17. Tickets: $33-$38. Information: 215-654-0200 or www.act2.org.EndText