IN "BROTHERHOOD," playwright John Richardson combines the Vietnam Aftermath drama with the Family Frontporch play.

Thoughtfully acted and attractively produced at New Playwrights' Theater, the resulting hybrid is an insubstantial and underdeveloped evening that loudly attempts to prove its maleness, then goes all soft to show how sensitive it is.

Richardson's story is scant but he builds his play around a neat conceit, superimposing Now and Then as we witness simultaneously the events of summer evenings in 1969 and 1981. Globetrotting brother Jack, returning after a 12-year absence has missed his father's funeral that morning, so there is recrimination, then a reconciliation of sorts with his younger brother Charles, now a lawyer. We also watch their younger selves: Jack was a feckless hippie, experimenting with marijuana; Charles was a straightlaced worrywart law student.

But it is the character of older brother Digger, present only in that earlier summer, that is the most interesting. Crewcut, chest-thumping Digger has flunked out of school, gone through a tour in the Marines and returned to shepherd his brothers with braggadocio and bullying affection. But Digger secretly feels he has failed his father, so he leaves to reenlist and never returns, leaving his brothers to confront their memories of him and their father on this still summer night.

Richardson has begun to get at the deep affinities and antipathies among brothers, and has a knack for their eloquently inarticulate dialogue, with feelings communicated through interruptions and punches. But "Brotherhood" feels like an early draft; Richardson can't conceal that his characters really don't have much to say, and most of that has been said before.

Director William Partlan and his able cast almost succeed in disguising the play's lack of focus. Partlan sets the actors to kicking garbage cans, swilling beer, wrestling, playing basketball -- at times it's more like New Playwrights' Athletic Club. All five actors -- Christopher Hurt, Christopher Pickart, Mark Mendez, Paul Morella and Rick Foucheux -- turn in vigorous, believable performances, and there is an uncanny resemblance between the younger and older Jack and Charles.

Michael Franklin-White has created the quintessential small-town summer-night front-porch set, and Daniel MacLean Wagner's moon-drenched lighting has much to do with evoking the play's sweetly melancholy mood.

BROTHERHOOD -- At New Playwrights' Theater through April 27.