AFTER MAKING A NAME for themselves with a series of finely wrought melodramas and unconventional comedies in their first several seasons, Third Rail Repertory have increasingly tried their hand at slapstick—last season's Dead Funny was a pie-in-the-face homage to Benny Hill-style comedians, while this season's opener The Lying Kind is a morbid twist on a British farce.

It's a farce that quickly distinguishes itself with higher-than-normal stakes: It's Christmas Eve, and two bumbling young police officers have been dispatched to inform an elderly couple that their daughter has been killed in a car accident. It's a great setup, and the show's opening scene will be familiar to anyone who's ever hovered nervously on a doorstep, afraid to ring the bell. The two police officers stand on the stoop, torn between a desire to get on with their work so they can go enjoy a Christmas dinner, and a mortified awareness of just how grim their errand really is.

And once the door finally opens, it's as bad as they feared: An adorable little old man stands before them, the perfectly cast Richard Mathews, who cheerfully plays into the protective impulses any humane person will have toward such a sweet, frail old gentleman. Throw in a crazy wife who doesn't know what year it is, and a crusading member of a local anti-pedophile organization who suspects the police might actually be involved in some sort of child molestation coverup, and the hapless coppers quickly find themselves involved in a tragedy of errors of their own making, as they prove completely unable to fulfill the mission they've set out on.

This is "gotcha" comedy, and it wouldn't do to ruin too many of the punchlines. Misunderstandings pile up right and left, and the elderly couple at the center of it all remains blissfully ignorant of their daughter's death. And so the play's best jokes come with a built-in wince, a twinge of guilt at laughing in the face of someone else's misfortune—a marriage of the comic and tragic that grounds even the script's sillier convolutions.

But while playwright Anthony Neilson's script deliberately toys with the line between the comic and the tragic, on opening night, laugh lines were still sorting themselves out. Madcap pacing is required to get through some of the show's more arduous jokes—in particular a storyline about how the elderly wife, played by Jacklyn Maddux, is prone to act out inappropriate flashback sequences—and as the characters navigate increasingly outrageous situations, the humor can feel strained. In particular, Isaac Lamb as the (female) anti-pedophile campaigner has a bullish, over-earnest bluster that effectively dampens the laughs in every scene he's in.

But for all that some scenes drag, and some jokes splat limply against the fourth wall, The Lying Kind's got a comedic saving grace in the form of ensemble member Michael O'Connell, who once again assumes the role of a bumbling police officer (see: last season's A Skull in Connemara). O'Connell proves an incredibly deft comic actor, embodying a buffoonish character with surprising subtlety. It's worth sitting through two hours of hit-and-miss slapstick just to see O'Connell's awkward striptease—with one hesitant thigh slap, he wrings more laughs from the audience than some of the script's more ostentatious plot twists combined. It's truly an impressive performance, one that does full justice to Neilson's gleefully morbid script.