"Lovely" and "touching" aren't adjectives usually associated with the hilarious but extremely acerbic English playwright Alan Ayckbourn. Still, those are the words that sum up Ayckbourn's "Communicating Doors," which opened Monday night at the Round House. Slapstick funny in places and just plain funny most everywhere else, Nick Olcott's production achieves, in the end, a kind of sweetness audiences don't often get, sweetness as deep as sorrow.

In a tony gray and gold hotel suite (glamorously designed by Tony Cisek), a woefully unassertive dominatrix who calls herself Poopay (Jane Beard, arrestable in tight black patent leather) finds herself in a bit of a pickle. The elderly man who hired her, Reece (Mitchell Hebert), turns out to want her to cosign, as witness, a written confession of his many crimes, which include allowing the murder of two wives.

Meanwhile, Reece's assistant and protector, Julian (Marty Lodge), who apparently did the actual murdering, is lurking around in a nasty mood, not at all sure he can trust his old employer anymore. When Julian decides Poopay knows too much and is expendable, in panic, she locks herself in what looks like a tiny closet but is, in fact, a passage into--

The past!

Yes, it's a science fiction story up there on the Round House stage, a time-travel fable in which one of humanity's sneaky sentimental fantasies--that the awful past can be altered, wrongs righted, sins forgiven--is charmingly fulfilled. It's almost Dickensianly heartwarming.

The startled Poopay (who soon confesses her name is Phoebe) finds herself in exactly the same hotel suite, but 20 years earlier--in the very place and on the very night, in fact, that Julian tossed Reece's second wife, Ruella (Kathryn Kelley), out of the window.

At present--if the term has meaning in a play like this--Ruella is very much alive. A sensible woman with an admirably open mind, she quickly figures out what's going on and devises a plan to save not only her own life but also those of Phoebe and Reece's first wife, Jessica (Jennifer Gerdts).

Olcott has exactly the right touch for this kind of nonsense--things get frantic and absurd but never actually fall into the unreal--and he has the cast for it. This is an ensemble that understands comedy (it also includes Delaney Williams as a dim hotel detective).

Kelley is streamlined and elegantly self-possessed, Beard is quirky and vulnerable, Lodge is slimy, Williams is dopey, Hebert is cantankerous and then, in a change of heart, warm--and they're all deliciously funny.

"Communicating Doors" may lack Ayckbourn's customary bite but his wit is all there. "You know who you remind me of?" Julian tells the dressed-to-dominate Poopay. "My mother." Poopay, who is from 2014, fills Ruella in on how computers have taken over the sex industry: "You sit at home, mouse in one hand, joystick in the other."

Though it's always speedy, the play sometimes trips and stumbles in its over-complicated plot. Things get a bit slow while Ruella is figuring things out and devising her plan. And a scene about dumping a body off a balcony goes way out of control, as if it were edited in from some Laurel and Hardy film.

"Communicating Doors" is light, on the verge of being nothing but high-quality comic entertainment. But it has subtle shadings. Like much of Ayckbourn's work, it's an outre take on farce. People dodge in and out of doors here just like in any old hotel sex comedy, but the doors lead into the past and the future and other people's lives, and, ultimately, out of the traps of our mistakes and into hope.

Communicating Doors, by Alan Ayckbourn. Directed by Nick Olcott. Lights, Ayun Fedorcha; sound, Daniel Schrader; costumes, Rosemary Pardee; props, Tommy Wang. At the Round House Theatre through Nov. 28. Call 301-933-1644.

CAPTION: Mitchell Hebert and Jane Beard in "Communicating Doors."