The young cast of Signature Theatre’s new play, “Really Really,” pulls off a nuanced, unsettling and relatable production.

In 2007, playwright Paul Downs Colaizzo, then 21, set out to write something explaining the mindset of his generation. What he came up with was “Really Really,” currently in its world-premiere run at the Signature Theatre. A savvy and sad play, it tells the story of a group of college students trying to balance relationships, ambitions — and the aftermath of a party at which a violent crime may have occurred.

The characters are both confused and driven souls, certain that they have to figure out what they want in order to get it but terrified of picking the wrong goal or of losing themselves along the way. It’s an of-the-moment piece that’s ostensibly about Millennials — even though the current crop of 20-somethings is hardly the first generation to deal with these issues.

“It speaks to people on levels I didn’t imagine,” says Colaizzo, who’s surprised that older theatergoers have told him that his play speaks to their own youthful experiences. “Going into the rehearsal process, I was thinking, ‘This is going to be an exploration of this generation.’ And then, from the first day of previews, I was learning that older audiences relate to it. People have said, ‘That was me when I was in college.’”

If Colaizzo was initially concerned about the play’s appeal to older audiences, it wasn’t just about a potential generation gap. “Really Really” is graphic and profane, full of sex and anger — unusual for the Signature, which just wrapped a cheerful production of “Hairspray” and is known mostly for producing musicals.

“Signature’s done a really good job of preparing audiences not to expect ‘You Can’t Take It With You,’” Colaizzo says. “They said, ‘Don’t make any changes based on what you think our audiences want to see. Only make the changes you feel are best for the piece.’

“I was warned that I should expect people to walk out at intermission, but nobody has. So, if that’s my standard, I’m rocking it.”

Plot = Spoilers

Giving away even basic plot details would spoil the clockwork perfection of Colaizzo’s script — you’ll know what you’ll know exactly when he wants you to know it — so, we can’t tell you much about the story. Don’t be surprised if you and your date disagree wildly on the basic facts presented — and on the moral message of the play.

Signature Theatre, 4200 Campbell Ave., Arlington; through March 25; 703-820-9771.