The conundrums come thick and fast in Kenneth Lonergan's "Lobby Hero," the third in the Donmar's ongoing series of American imports. That Lonergan is already repped in London by "This Is Our Youth," which had its local preem less than a month before, makes for an impromptu season of work allowing a quintessentially American dramatist to be discovered anew.

The conundrums come thick and fast in Kenneth Lonergan’s “Lobby Hero,” the third in the Donmar’s ongoing series of American imports. (“Proof,” starring Gwyneth Paltrow, is next.) That Lonergan is already repped in London by “This Is Our Youth,” which had its local preem less than a month before, makes for an impromptu season of work allowing a quintessentially American dramatist to be discovered anew. The twin openings also afford the opportunity to compare a slacker tragicomedy richly seasoned in Chekhov to one with an ethical heft that even Arthur Miller might find a bit much. And yet, even when the moral stew that is “Lobby Hero” threatens to boil over, Lonergan’s gift for gab sets him apart: “I’m a security specialist,” insists Jeff (David Tennant), the mock-heroic lobby attendant of the title, and Lonergan himself is a decidedly special anatomist of both language and the impulsive stirrings of the heart.

Seeing the two plays in close succession, one is tempted to remark that there’s hardly another playwright on either side of the pond who so skillfully reanimates the time-honored ritual of the mating dance. There’s a direct link between the prickly yet tender give-and-take of the well-heeled West Siders in “This Is Our Youth” and the hesitant to and fro that brings the avowedly awkward Jeff into the romantic orbit of rookie cop Dawn (Charlotte Randle), who finds a haven of sorts in designer Robert Jones’ sparely designed lobby.

But whereas the lives of the trio in the prior play involve onstage drugs and offstage parents, “Lobby Hero” lands each character in a precise ideological dilemma, rather as if the four had all been drafted as contestants on popular BBC radio program “The Moral Maze.”

William (Gary McDonald), Jeff’s superior, has been asked by his brother to provide the alibi for a murder that may have resulted in the death of a 27-year-old single mother and nurse. Jeff becomes privy to this information at the same time as he is clocking a deception closer to hand — namely, an awareness that Dawn’s partner on the beat, a senior officer named Bill (Dominic Rowan), is carrying on a dalliance with a prostitute in Apt. 22J.

Dawn, in turn, has risked her own probationary period on an incident of police brutality in which she needs Bill’s support. She won’t get it if Jeff spills the beans, with Bill making brutally clear that the gossip pathway leads potentially to death.

Who’d have thought a night shift could be so packed with psychological and ethical subterfuge? The answer: a playwright capable of delivering an enclosed environment in which conscience exists to be gnawed at, with the cancers of sexism and racism making themselves felt, too.

The result leaves “Lobby Hero” on a deliberate seesaw between public posture and personal desire — a mix that tends to excite English critics, but left this American missing the organic, seemingly plotless agglomeration of feeling that gives “This Is Our Youth” such punch. “Lobby Hero,” for all the heavy ruminations it puts forth, is oddly sentimental, too, with numerous exaltations of the seemingly wayward Jeff to contrast with the very real wilderness that brings “Youth” to its wrenching close.

Still, Lonergan is always an actor’s delight, and so he proves again here, with director Mark Brokaw — repeating his New York assignment — shifting the balance somewhat among the play’s foursome. Tennant isn’t the natural goofball cut Off Broadway by Glenn Fitzgerald; the lanky and always likable Scottish actor comes more slowly, if eventually winningly, by his depiction of a loose talker enmeshed in a labyrinth of right and wrong. And though McDonald needs to relax into the part of William, Rowan and Randle have their roles down pat.

Playing a supposed “genius cop” who is ill-prepared for the play’s various sacrifices of confidence, Rowan can be comically arrogant one minute (asked for his “autograph,” his Bill takes the word at its most literally grandiose), chillingly brusque the next. Randle is even better, playing a woman caught up in a “bad world” who enables herself to see the good.

Lobby Hero

Donmar Warehouse; 251 seats; £20 ($28.75) top

Production

A Donmar Warehouse presentation of a play in two acts by Kenneth Lonergan. Directed by Mark Brokaw.

Creative

Sets and costumes, Robert Jones; lighting, Rick Fisher; sound, Fergus O'Hare. Opened, reviewed April 10, 2002. Running time: 2 HOURS, 35 MIN.

Cast

William - Gary McDonald
Jeff - David Tennant
Bill - Dominic Rowan
Dawn - Charlotte Randle
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