Manbites Dog Theater winds up its 25th season of intelligent examination of the human beast with another X-ray of a play, through June 9. Performed in the round in Manbites’ intimate space, Daniel MacIvor‘s two-man In On It effortlessly sweeps the audience into its populace. We are the world of people that surrounds the two actors. We can’t always see them because sometimes the light is right in our eyes, no matter where we are in the room, and they can’t see us, or even themselves, very well either, for the same reason. But we can hear them, loud and clear, in this smart-but-not-showy theatrical, where two actors play two men playing two actors who portray several characters, male and female, trying to figure out something about living and loving and dying. The script whirs around like a three-bladed fan: the two men’s love story gives place to the story of the play they are making, which in turn gives way to the story within that play; as the fan moves faster, the distinction between the blades disappears — it is all one story.

Our two actors are Matthew Hager and Gregor McElvogue. They play This One and That One, the two men struggling to create a play and to create their lives. Along the way they probe into heavy matters, like the intersection of accident with planned action, like the difference between happy and “not sad,” like the difference between living and being alive — or not. On preview night, Hager and McElvogue were amazingly polished in this 80-minute talkathon. Hager is quite young — this is his first show at Manbites — but he’s a graduate of the School of the Arts, and of UNC’s Department of Dramatic Art (2011). As people used to say, he’s a credit to his raising. All the role-swapping in the nested stories gives both actors a chance to show their range of nuanced interpretation, and Hager holds his own beautifully with the more experienced McElvogue, whose very large presence can sometimes make other actors hard to notice.

McElvogue, as usual, somehow gets us into the palm of his hand about three seconds after he appears on stage. In this play, he occasionally glimpses us, the surrounding crowd, and with a slightly sheepish smile, rakes us with a flicking glance of his knowing eye. It is ravishing. His character, That One, is bullishly honest, antic, funny. He’s willing to laugh, to be angry, to unshield himself before his lover — and by extension, before us. McElvogue’s performance here is heart-stretching; it caused me to tear up repeatedly, between outbursts of laughter. You really do not want to miss him dancing to a ridiculous Lesely Gore song (just one element in a rich sound design by Quran Karriem).

The whirling tandem dance of MacIvor’s script is kept on tempo by Dana Marks’ flawless direction. Not every actor, even one as skilled as Marks, can successfully make the transition to directing, but Marks has crossed the chasm. This is mature work, executed with delicacy. Marks has balanced idea and action, speech and motion very precisely, and staged the whole play like an extended dance, with interior choreography by Jeffrey M. Moore. The play is ripe with unwieldy feeling, but it is also very funny. Its humor is sometimes broad, but never coarse — it’s for thinking people — and Marks gets the most out of it by using a light touch. Nothing sags into bathos, or flitters off into parody or stultifies with self-importance. With just enough space and just enough crowding, the pacing and timing are pretty much perfect. In On It is a stand-out among the many great productions in Manbites Dog’s quarter-century of humane dramatic art.

In On It continues through June 9. See the sidebar for details.