Tony K. Nam, Cristina M. Ibarra and Erica Chamblee in Mosaic Theater’s “Sooner/Later,” through June 16 at the Atlas Performing Arts Center. (Stan Barouh)

Who needs a dating app when you have a daughter like Lexie? The shrewd, perky teenager we meet at the start of “Sooner/Later” not only masterminds her single mother’s social life, but also offers encouragement and fashion tips. A budding intellectual, Lexie ponders how romance aligns with the theory of probability: Her graph of the relevant variables, in a notebook, displays her mother’s dating failures in brutal plunging lines.

Local playwright Allyson Currin’s ingenious characterization of Lexie is the highlight of ­“Sooner/Later,” an often funny, ultimately moving, occasionally slack play that weaves rom-com elements into more-sober musings about parenting and loss.

Supported by the Trish Vradenburg Play Commission, which focuses on female playwrights, Currin has revisited “Sooner/Later” since its 2018 premiere, and the story is now set in Washington. The production is part of Mosaic Theater’s Locally Grown Mosaic initiative, which nurtures area artists.

In the spare, handsome production, directed by Gregg Henry, Cristina M. Ibarra delivers a marvelously vivid portrait of Lexie, whose role in the household proves more complicated than might initially appear. The performance helps this naturalism-tweaking play land its insights into bittersweet family dynamics and existential yearning.

Not that Ibarra’s is the only terrific turn in this production. Portraying Lexie’s mother, Nora, whose dilemmas are at the heart of the story, Erica Chamblee creates a vibrant, appealing portrait of enlaced prickliness, insecurity and moxie. A no-longer-young apparel-industry professional who has little patience for chitchat, Nora instinctively bristles at Griff (the very good Tony K. Nam), a not-so-suave game designer who witnesses her dating fiascoes in a coffee shop.

With the riptide of attraction roiling Nora and Griff’s free-flowing hostility, the early coffee-shop conversations in “Sooner/Later” are sailing in rom-com waters.

That’s a fine choice, in theory: Four hundred years after Shakespeare birthed Beatrice and Benedick, why should the likes of Netflix have all the fun with kooky-courtship stories? But in practice, the early conversations between Nora and Griff could use polishing. The scenes lack the consistently sharp, taut, zinging repartee and obstacle-spiked plotting that might generate delectable romantic comedy.

Still, these scenes do contain tangy exchanges, as when Griff decides that his future with Nora absolutely depends — go figure — on how she answers the riddle-like question “What do you say in an ice storm?” (Her punning answer impresses him.) And the name of Nora’s go-to coffee shop, by the way? Grounds for Impeachment.

Stark and minimalist — except for a fantastical bureau drawer — Debra Booth’s set hits the right notes of unsentimental modernity while allowing the play to pursue space-time-flouting twists. (Kyle Grant devised the bold lighting.) Danielle Preston’s costumes, including the dressy outfits Nora reluctantly dons for her dates, speak to character and predicament.

The characters’ predicaments register with increasing poignancy as the play proceeds. Life turns out to be more rewarding, difficult and unpredictable than the charts in Lexie’s notebook suggest.

As the precocious teenager puts it, at one point, “Certainty is for sissies.”

Sooner/Later, by Allyson Currin. Directed by Gregg Henry; sound design, Evan Cook; properties, Willow Watson. About 80 minutes. $20-$65. Through June 16 at the Atlas Performing Arts Center’s Sprenger Theatre, 1333 H St. NE. 202-399-7993. mosaictheater.org.