Love in a Glass Jar, Ribbons

Peacock, Abbey Theatre, Dublin ***

Does a series of 20-minute plays, commissioned according to a theme and staged as rehearsed readings, represent a shot in the arm for new writing at the Abbey or a creative dead end? It's a question of form rather than talent or support: a good 20-minute play is something complete and self-contained rather than a pitch for a longer work, and such plays rarely find further life on the stage.

Here, two earlier shorts, Nancy Harris's Love in a Glass Jar (2008) and Elaine Murphy's Ribbons (2009), receive full production in a double bill directed by Oonagh Murphy.

Although both plays share common themes of intimacy, disconnection and reconceived families, their more striking similarity is how they address the task, not so much building up a story as constructing brief riddles to unravel.

Two strangers meet in a boutique hotel room in Harris's piece, which expertly plays on audience expectations with teasing clues and false trails.

"I'll give you some money," Arthur Riordan's chatty property developer tells Michele Moran's visitor, who produces a stack of pornography with business-like efficiency. We assume the rest. "Don't worry about money," she responds uncertainly, "I left them my credit card." We guess again.

Harris's writing is so full of deftly delivered character detail, lightly trailed wit and sly social critique that the play's twist is hardly important. Suffice to say that this is an artificially accelerated relationship, but it shifts gears from comic set-up to a quite poignant meditation on family.

Ribbons shares some of that emotional territory, but it ushers the audience more immediately into a guessing game. What is the relationship between Ruth McCabe's silver-haired, guarded Glenda and Chris Newman's angry young Lewis, whose deadened dialogue ("I wasn't sure you were coming." "Me neither.") suggests a long-estranged pair?

To answer that question would deflate the whole play, which rests on a sudden moment of revelation like a load-bearing structure. Although Elaine Murphy touches on some fascinating, uncomfortable truths about secrecy, selfishness and betrayal, they aren't given the room to develop, and you feel intrigued but unsatisfied.

Oonagh Murphy's production, designed with clever economy by Lydia Concannon and expressively lit by Eoin Stapleton, is in smooth command of the rhythms of both pieces (just like Derek Conaghy's sound design). But despite this production's best efforts, the fascinating ideas of each play seem confined to the limbo of a writing exercise.