By John Lyle Belden

In “Adults,” the new play by Jeremy Grimmer in its world premiere with Fat Turtle Theatre Company, the characters are all adults.

They are consenting adults, okay with having sex whenever they want. They are adults who are free to gather and play video games at any time. They can feel comfortable enough with any situation to not let it bother them. They can say “I love you.”

“Life isn’t easier, just because it looks freer,” says E.J. (Colin Landberg). This is his house, which he inherited and now lives in alone. One night he brought home Sarah (Afton Shepard), who decided to be “not married” for one day. She awakens shocked to find him fixing her breakfast — is this the way adults do this? Charmed and conflicted, she engages in one more romp before going home to her husband — then returns about once a week. Her marriage is crumbling, having lost its intimacy, but she has kids so she doesn’t divorce; it seems like the adult thing to do.

Old high school friends Meg (Kim Egan), Seth (Josh Turner) and Fred (Brad Root) come over to E.J.’s to play a shared online wargame. While each has a life (and Seth a wife) outside this gathering, all that matters here is leveling up and what snacks are being offered. They even eventually meet Sarah (introduced as E.J.’s neighbor) and are totally cool with her. Why wouldn’t they be? We’re all adults here.

Thus we go through five years of an affair and unusual friendships, the events that lead up to today, when our couple has to make hard — adult — choices.

Directed by Fat Turtle co-founder Aaron Cleveland, this script feels almost too polished to be new, and the cast give solid performances, especially Landberg as easy-going heart-on-sleeve E.J. and Shepard as sweet but girl’s-got-issues Sarah. While even the characters note the improbability of their situation lasting so long, this only goes to the overall atmosphere of arrested development throughout the cast. We find that it’s not enough just to be an adult; at some point you also have to grow up.

Be warned that another theme element is food — starting with the awesome smell of bacon for the first scene in the air before the play even starts. It might be best to have dinner before the show.

This sharp drama nicely leavened with comic elements is worth the effort to find, with one remaining weekend of performances, Thursday through Sunday, Jan. 17-20, at Theater at the Fort, 8920 Otis Ave. on the grounds of old Fort Benjamin Harrison off of North Post Road in Lawrence. Get info and tickets at fatturtletheatre.com.