"The New Naturals" is two-thirds of a great novel.

Gabriel Bump's satire boasts lively prose that feels like it races to make its points ("they were in a small plastic back seat, moving slow toward the police station, hands behind backs, without wine, blankets, water, clouds, peace"). The subject — dissatisfied with our unhoused/uninsured/unwell world, dreamers create a new society underground — feels up-to-the-minute. And natural, conversational dialogue drives the book to such an extent that for pages at a time, it's almost like a play.

The first half of Bump's followup to "Everywhere You Don't Belong" reads like a dream, with compelling people making interesting, unexpected choices. The main characters are pregnant Rio and husband Gibraltor, who are determined to make a better world for their unborn daughter. Frustrated by the lack of progress toward justice and equity in the above-ground world, they start a commune of sorts, underground, where they welcome others who feel disenfranchised.

Bump follows several others, including a pair of unhoused men from Chicago and a worn-out journalist named Sojourner, as they learn about and commit to Rio and Gibraltor's dream. It's a large cast of characters, which might be risky in less sure hands, but Bump makes them specific, engaging and real.

The trouble is the utopia — which, not surprisingly, becomes a dystopia. After a couple hundred pages of preparing us for the dreamed-of society, "The New Naturals" skips over how it works, proceeding almost directly from utopian dreams to collapse, which comes about because a deus-ex-machina benefactor grows bored with the project.

Bump makes his points: Maybe, instead of starting something new, we should fix what we have? Maybe it's a mistake to rely on a one-percenter to help the rest of us? But the last section of the book disappoints because it starts to seem like "The New Naturals" is a bait-and-switch.

The New Naturals

By: Gabriel Bump.

Publisher: Algonquin, 295 pages, $27.