ALL THE WAY HOME - At the Olney through August 5.

James Agee's perfect representation of the spectrum of conflicting emotions that comprise mourning, "A Death in the Family," is being done at Olney Theatre in its stage version by Tad Mosel, "All the Way Home." The second act, in which it is gradually understood that a beloved person is dead, is about a catharsis as the theater can administrate.

Pat Karpen, as the new widow, careens between intense contemplation of the commonplace and the eternal, between screams and laughter, between tenderness and fury, between desolation at the future she will not share and jealousy of the parts of the past she has missed, between imploring God for relief and imploring her relatives to have a cup of tea. The only consistency is that her tongue keeps darting out of her parched mouth.

It's an extraordinary performance, vibrating with shocking truth. No majestically even representation of bereavement can seem genuine in comparison. Others - notably Jen Jones, as the widow's tough and compassionate aunt; John Wylie, as her fond but aloof father; and Guy Michaels, as her young son using the celebrity of his orphaned state to gain status with the sidewalk crowd - ably play the subsidiary roles of this grim but familiar family pageant.

But unfortunately the mourning has been clumsily set into a family drama in which first the possibility of death, and then its legacy of change, are repeatedly made obvious.

The point intended is that tragedy has transformed an otherwise ordinary household, with its modest share of pleasures and conflicts, into something terrifyingly lofty. But heavy-handed efforts to show that death can take people out of sequence abound in the first act, when the stage is cluttered with the elderly, the infirm and the apparently immortal. The same actress who is electrifying as a widow is cloying in the first act as a wife who scolds with a kiss, and verging on the platitudinous in the latter half of the third act, when she bravely shoulders the father's part along with her own.

The director who has so ably orchestrated the tragedy, Leo Brady, has the family running around in a silly fashion, apparently trying to find their misplaced southern accents, before tragedy strikes. It seems unfair to David Snell, who plays the good but vaguely philosophically troubled young husband, that the plot requires him to be the only one unable to redeem himself in the second act.