In “Civil War Christmas: An American Musical Celebration” at the Huntington’s B.U. Theatre,  playwright Paula Vogel aims to build the kind of broad tapestry that’s the stock in trade of Charles Dickens and E. L. Doctorow, but in the end, it may serve as a reminder of why novels are novels and plays are plays.

Paula Vogel is thinking big these days – so big, perhaps, that her ideas can’t be contained on the Huntington Theatre Company’s stage ... or any stage, for that matter.

With “Civil War Christmas: An American Musical Celebration,” playing through Dec. 13 at the Huntington’s B.U. Theatre in Boston, she’s cooked up a sweeping epic that never quite sweeps us up.

She envisions the streets of Washington, D.C., teeming with life (and stories) on Christmas Eve 1864. She’s clearly intrigued and inspired by the notion of chance encounters and the sometimes-fortuitous, sometimes-tragic ways our paths cross. She populates the stage with newly freed slaves, rebel soldiers without a cause, Abe Lincoln trying to save the Union and Mary Todd Lincoln trying to buy a Christmas tree. Vogel aims to build the kind of broad tapestry that’s the stock in trade of Charles Dickens and E. L. Doctorow, but in the end, “Civil War Christmas” may serve as a reminder of why novels are novels and plays are plays.

It’s so big that Vogel, as talented as she is, can’t quite get it all together. The stories parade across the stage with little impact. Yes, she’s cooked up lots of soap opera drama – a black Union sergeant about to blow the head off a neophyte rebel soldier, John Wilkes Booth and company plotting the assassination of President Lincoln, and a fleeing slave desperately searching for her lost child who won’t survive this freezing night on the streets of D.C. But it’s hard to muster up a truly emotional connection with any of them.

It’s a math problem. None of the 90 or so characters ever really gets enough time to develop their story, or make us care. We understand their plights, but we never really empathize with them.

The play is also slowed by exposition. With so many intersecting stories, Vogel is forced to commit a cardinal sin of playwrights – she doesn’t show her story, she tells it. The folly truly comes home when a character says something like, “she put the box into the wagon” just as the character, well, puts the box into the wagon. Suddenly, it doesn’t feel like theater anymore; it feels like a novel, abridged, and crammed onto a stage, where characters tell us who they are, how they feel, and why. It’s a surprising misstep from Vogel, a playwright with an unerring ear and eye for what’s dramatic.

The Huntington, ambitious and capable, rarely has trouble chewing whatever it bites off. But, as ably as director Jessica Thebus shuttles the army of characters about the stage, Vogel’s big ambition seems to stress all aspects of the company. When we meet the members of Lincoln’s cabinet, one of the “men” is wearing a hoop dress from a previous scene when he/she was Elizabeth Keckley. I know we’re supposed to forgive – and chuckle at? – the fact that the stagecraft is being laid bare. But a moment like that – almost a Marx Brothers moment – confuses, or even destroys, whatever reality Vogel is trying to build.

It’s not the only time Vogel and Thebus struggle with tone. The whole play feels appropriately dead-serious at the start, but when actor Ken Cheeseman has to play a horse who not only understands English, but also speaks it, the play has suddenly lurched into some alternate reality. The Disney-fication of animals makes you feel like Vogel isn’t quite taking the whole thing seriously, so why should we?

There’s joy in watching local talent get to spread its wings on the Huntington’s wide stage. Cheesemen, who becomes a dead ringer for Abe Lincoln with just the iconic beard and a new part in his hair, is always a treat to watch and he deserves more opportunities like this. And I’ve always respected the work of Jacqui Parker, but she’s showing me things I’d never seen in her before – most notably, her ability to command a huge stage.

But there’s surprisingly little joy in the way Vogel wraps up this “Christmas” present. It’s disappointing that we can predict the way all the stories will conclude.

A CIVIL WAR CHRISTMAS Huntington Theatre Company,  264 Huntington Ave., Boston. Through Dec. 13. $20-$82.50; 617-266-0800,