There is a lot going on in this novel, Nicole Helget's "Stillwater," set in the Minnesota town between the 1830s and the 1870s.

We have twins separated at birth, a fur trapper with three wives, robber barons, escaped slaves, a priest who helps them, a nurturing nun, a whorehouse that also serves as a stop on the Underground Railroad and the lumber trade that powers Stillwater's prosperity.

Beaver Jean's tiny third wife runs away, pregnant, and abandons her babies in an orphanage run by Mother St. John, who names them Clement and Angel. Clement grows up there, cared for by the Big Waters, the Mother's American Indian assistant, while Angel is adopted by a wealthy family. Ironically, Clement's is the happier fate because Angel, until the day of her marriage, is repeatedly poisoned and then healed by her mother, who is trying to demonstrate to her husband what a solicitous caretaker she is.

Despite the colorful plotting and characters, the novel feels oddly stillborn, willed into being rather than growing organically. The book's characters wear their personalities as labels rather than developing believable identities. Helget proceeds through her novel with a detached air that I found disconcerting.

Some plot turns feel random. Why does Angel creep up behind Beaver Jean, kill him with an ax, leaving her brother to take the blame and serve the penalty? Why does the black boy Davis, who grows up raised by kindly whores, suddenly up and die? And why does the twins' birth mother wind up a nun?

But Helget's language, often over-the-top, can be rousing fun. Here is Beaver Jean's reason for wanting a third wife alongside his "squaws": "He wanted one to climb all over him like a squirrel on a tree, rather than rub like a heavy bear against his trunk, as his wives were apt to do. One who offered tender white meat like that of a prairie chicken or grouse, rather than the tough red meat of a buffalo or bear. He wanted a little delicacy."

The stories and their protagonists left me curiously unmoved. Only the town of Stillwater, defined by its waterway, feels like a real character, a well-imagined place. The opening scene, describing an epic logjam on the St. Croix River, is mesmerizing. It begins, "Thousands of white pine and tamarack logs were hung up, crisscrossed, and tangled to form a dam as tight as a sinner's fingers. … The usual roar of the St. Croix was eerily quiet, and stagnant pools sat rank among the logs."

Brigitte Frase is a longtime book critic in Minneapolis.