Eric Lucas, left, and David Bryan Jackson are co-stars in Scena Theatre's “The Seafarer.” (Veronica Hunter/Courtesy of Scena Theatre)

When you sit smiling for two-plus hours in a theater and don’t realize it until your face starts to ache, you know you’ve sojourned for a bit in theatrical heaven.

It’s a place theatergoers don’t get to visit often enough. Too many jarring notes, onstage and off, can impair your pleasure.

Not so with Scena Theatre’s crackerjack production of “The Seafarer,” at H Street Playhouse through May 20, which works like a charm from lights-up to the final blackout. Watching the Irish dramatist Conor McPherson’s fable about four men who engage in a card-playing showdown with the devil himself — although three of them don’t realize what’s happening — is heavenly fun. Scena’s artistic director, Robert McNamara, has staged the play with dead-on emotional and comic insights, inspired casting and a willingness to make the play’s spiritual content crystal-clear, yet not in the least cloying.

“The Seafarer” gets its title and some of its meaning from an Anglo-Saxon poem about life’s hardships and the importance of faith and the afterlife. McPherson has said in interviews that he also mined Irish folk tales about the devil walking among men.

The men are more than a little the worse for wear, thanks to their profane, whiskey-soaked Christmas Eve revels in a grimy house on the outskirts of present-day Dublin. They all have tragic flaws, past transgressions and wrecked relationships to answer for. And the dapper Mr. Lockhart has come to collect.

But in the second act, a moment of simple forgiveness among the friends threatens to upend Lockhart’s plans. McPherson’s 2006 play, first produced in London, then on Broadway in 2007-08, where it garnered a Tony nomination for best play, is a parable on Christian themes. Yet it is open to universal and secular interpretations — that humaneness is perhaps as important as faith. This production lends truth to all of that.

Richard (Joe Palka), a fellow in later middle age who has recently lost his sight, hosts the festivities in his parlor. The room is designed with built-in grime by Michael C. Stepowany, adorned with pictures of Pope John Paul II, JFK and Jesus with a sputtering, electric sacred heart. Richard’s younger brother Sharky (Eric Lucas) has recently moved home from a job gone sour, and he seems to have other, darker memories, too. Palka’s Richard, perhaps fueled by his new disability, fires alternating fusillades of crankiness and holiday cheer at all and sundry. Lucas’s Sharky is sullen, trying shakily to pass an alcohol-free holiday.

Brian Mallon plays their longtime friend Ivan, a sweet-natured drinker who is always in the doghouse with his wife because he keeps forgetting to go home, forgetting his car, forgetting to stay sober. We meet him as he’s awakened from a night of knocking back shots with Richard and Sharky, sleeping on the rug in their spare room, and losing his glasses. Mallon’s Ivan is boyish, tragic and droll, even when silent.

David Mitchell plays Nicky, a clueless, happy-go-lucky chap who has earned Sharky’s hostility by appropriating Sharky’s girlfriend and car, in that order. Welcome or not, Nicky shows up Christmas Eve afternoon, bringing the smooth-talking, sharply dressed Mr. Lockhart (David Bryan Jackson), in whose mouth butter wouldn’t melt. As Lockhart, Jackson shifts from charm to vitriol and back with flair and, better yet, subtext.

Lockhart seems, at first, merely a pub acquaintance of Nicky’s, or perhaps a card sharp hoping to win a pile of euros off these losers. But when Lockhart gets a moment alone with Sharky, he makes it clear that he is Satan, coming to collect the soul for which he bartered years ago and offering a gut-churning description of hell. A few hands of poker will decide Sharky’s fate.

McNamara and the ensemble he has gathered, a mix of Washington actors and out-of-towners with strong Celtic roots (Mallon and Mitchell), blend their talents and accents to hugely satisfying effect. They give McPherson’s profane and sacred text as full a life as it deserves.

Horwitz is a freelance writer.

The Seafarer

by Conor McPherson. Directed by Robert McNamara. Set design, Michael C. Stepowany; lighting, Marianne Meadows; sound, Erik Trester; costumes, Megan Holeva; fight choreographer, Sun King Davis. About 2 hours 15 minutes, plus intermission. Presented by Scena Theatre through May 20 at H Street Playhouse, 1365 H Street NE. 703-683-2824;