No matter what the current ad campaign may intimate, adaptor Barbara Field and director Gary Gisselman didn’t set out to create “A Christmas Carol” running about the length of an average movie. The new lean and mean version of the Guthrie mainstay runs 90 minutes and is told in one act. For Gisselman, it’s the later part of the equation that’s most important.

“I had the idea of doing it as a one-act — there’s no reason to be a break after the Ghost of Christmas Past,” he says.

Doing it as a one-act keeps the story flowing, and focused on the core of the story: Scrooge’s journey. Drawing the piece over two acts forces some parts to be expanded when they may not be so drawn out. “The Fezziwig scene had grown to be very long,” Field notes.

“A Christmas Carol” first played on the Guthrie stage in 1975. Through the 35 years, the show has gone through numerous versions, interpretations and refinements. Part of the pressure, Field notes, is keeping the show focused. Each year, directors and actors will add a bit here or there, until the show started to take on too much weight.

The changes go deeper than the script and the staging. The casting has also gone through a shake-up, with veteran performer Peter Michael Goetz taking on the role as Scrooge and former Juene Luner Steven Epp playing Marley and the Ghost of Christmas Yet to Come.

For Field, whose work on the play for the Guthrie dates back decades, this means going back from time to time to pare the piece back. This year, the focus returned to Scrooge and the art of telling Dickens’ classic tale.

What make Scrooge such an intriguing character — and what showcases Dickens’ skill as a storyteller — is that he doesn’t transform. Instead, he remains the same character — but one who has had his heart opened by what he has seen, Gisselman says.

“We’re faithful to the book,” Gisselman says. “If we’re doing ‘A Christmas Carol,’ we have a responsibility to do the story. If you change it too much, you might as well write your own Christmas story.”

“A Christmas Carol” runs through Dec. 31 on the Wurtele Thrust Stage, the Guthrie Theater, 818 S. 2^nd St., Minneapolis. Tickets are $29 to $79. For information, call 612.377.2224 or visit online.