A scene or so into the Chicago Children’s Theatre’s staging of “Frederick,” a blazing orange leaf floats to the ground in slow motion. As the leaf spirals down, everyone on stage starts moving as if they are underwater. Someone hollers a prolonged “no-o-o-o-o-o-o-o-o-o-o,” the sound swelling like bubbles. It’s a classic disaster movie trope, applied to a charming children’s book. The result is hilarious. Given the recent snap of frost — and all that it portends — it is also seasonally spot-on.

In Suzanne Miller’s winning adaptation of Leo Lionni’s 1967 Caldecott Award-winning book, the titular mouse and his pals sing and dance (spirited original songs by Sarah Durkee and Paul Jacobs) as they move from the lazy days of summer into the fall and on to the chilly depths of winter. Along the way, they learn about work, loss, friendship and family. “Frederick” is a simple storybook, complicated by layers filled with wonder. As in all children’s stories worth their salt, how deep you want to dig is up to you.

★★★ 1/2
When: Through Nov. 11
Where: Chicago Children’s Theatre, 100 S. Racine
Tickets: $39
Info: chicagochildrenstheatre.org
Run time: 65 minutes, no intermission

On any level, that plummeting leaf is momentous. It’s a signal to the mice that the summer party is over. If they don’t get busy squirreling away food for the winter, they’ll have a Donner Party situation on their hands before summertime rolls around again.

So Sunny (Liz Chidester), Ernest (Joe Dempsey through Nov. 4, Shawn Pfautsch thereafter), Nellie (Nicole Laurenzi), and Baby (Leslie Ann Sheppard) get to work collecting nuts and seeds. But Frederick (Tommy Rivera-Vega) is too transfixed by the beauty of nature, the power of laughter and the wonders of storytelling to get any work done. While the others forage for food, Frederick collects leaves, snowflakes, sunbeams and flowers.

As it turns out, Frederick’s impractical whimsies have a very real value during the darkest days of winter. We all know a Frederick, the person so enchanted by beauty of a single candle flame, he doesn’t really notice that the house is on fire. Here, Frederick is a gentle dreamer, careening after butterflies and marveling at the industry of ants and the beauty of snowflakes. Nellie grouses that Frederick is selfish and basically putting everybody’s life at risk with his failure to collect food. But when Frederick goes missing in a snowstorm, even Nellie comes to realize how much he means to them.

Liz Chidester (from left), Leslie Ann Sheppard, Tommy Rivera-Vega, Nicole Laurenzi and Joe Dempsey play field mice preparing for the winter in Chicago Children’s Theatre’s production of Leo Lionni’s "Frederick." Background: multi-instrumentalist Jess McIntosh. | Charles Osgood Photo

Liz Chidester (from left), Leslie Ann Sheppard, Tommy Rivera-Vega, Nicole Laurenzi and Joe Dempsey play field mice preparing for the winter in Chicago Children’s Theatre’s production of “Frederick.” Background: multi-instrumentalist Jess McIntosh. | Charles Osgood Photo

Lionni’s story broaches ideas children will deal with their entire lives. “Frederick” is about learning to value someone who doesn’t think like you do. It’s about the passage of time and the irrevocable, unstoppable cycle of seasons. It’s about the importance of industry and dreams. It’s mice who tackle these topics in “Frederick,” but they are mice whose anthropomorphism gives them humanity.

So does director/choreographer Tommy Rapley’s marvelously invested ensemble. The actors are grownups, but they capture the playful spirit of children’s characters without pandering or talking down to their very young audience. (“Frederick” is best for ages two-and-up).

As Frederick, Rivera-Vega is as wide-eyed as Bambi, and equally appealing. He’s got a voice like a bell and competent keyboard skills that make songs like “There’s No Runnin’ Out of Joy,’’ well, joyful. Chidester’s Sunny is the group’s eternal optimist. Laurenzi’s nervous Nellie nicely illustrates how it’s possible to love someone and be completely exasperated by them. Dempsey gives Ernest an absent-minded professor-meets-Newsies vibe; as the others argue about seasons, Old Ernest is getting righteously indignant about the finer points of contrapuntal music. Sheppard’s Baby is all perky energy.

Durkee and Jacobs’ songs are delightful and made all the more so by a cast that plays its own instruments. Rivera-Vega handles most of the keyboards; Chindester plays a four-stringed banjo and Jess Mcintosh plays violin. Guitars, spoons, washboards, tambourines and drums also play into the soundscape, making the score as infectious as a hootenanny.

John Musial’s set takes the mice from verdant summer’s end to austere winter hidey-hole without missing a beat. Izumi Inaba’s costumes subtly enhance the mice’s primary personality traits: Frederick eventually dons an amazing technicolor coat that depicts the four seasons, complete with twinkling lights. Sunny’s winter garb is a skirt festooned with holly springs; her autumnal gear is all flaming russets.

“Frederick” manages a difficult feat: It celebrates the imagination, dreams and the ability to truly see the wonder of the world. It also depicts the value of work. It’s not always pleasant, but it is always pleasanter when you’re among friends working toward the same goal. Silliness and seriousness exist side-by-side in “Frederick,” opposite sides of the same coin. You can’t have one without the other. “Frederick” captures both with wit and humor.

Editor’s note: Access Weekend for “Frederick” is October 27-28, with special services that include a pre-show tour of the set for guests who are blind or have low vision; an ASL and live captioning performance; a sensory-friendly performance for Down Syndrome children or children on the autism spectrum. Modifications are made to lighting, sound and music to avoid sensory overload, with a nearby Quiet Room. For Access show times and more information, visit chicagochildrenstheatre.org