A pervasive, lingering sense of the vague is perhaps the most unsettling thing about “The Farther Shore,” Matthew Eck’s insular, implosive debut — a slim war novel filled with more immediately disturbing matters. Despite his assertively precise language and hard, bullet-sleek sentences, the menace of vagueness itself is at the heart of Mr. Eck’s portrait of modern warfare; it becomes the only homing signal you will need to negotiate this particular fog of war. Set in an unnamed city during an unnamed conflict at an unnamed time, one need look no further than Mr. Eck’s biography — he enlisted in the Army in 1992 and served in Somalia and Haiti — to confirm that “The Farther Shore” takes place in 1993 Mogadishu, a few months into the American-led UN intervention that has already spawned several nonfiction treatments.

In “Black Hawn Down” (1999), Mark Bowden took a damning look at American military strategy in Somalia, suggesting that a blanket adherence to tightly drawn rules of engagement in such a complex, vaguely understood and vagarious situation led to the deaths of 19 American troops and more than 1,000 Somalis on a single day in October 1993. Moreover, Mr. Bowden suggested, the failure in Somalia portended ominously — and pivotally — for the future of American military strategy as an extension of its foreign policy. What Mr. Eck achieves in focusing attention on the identifying details of his setting is solidarity with post-Somalia soldiers, those who participate in post-September 11, 2001, conflicts and this new, post-modern style of warfare. The moral and logistical chaos of that experience — in all its terrifying specificity — is what will resonate, echoing Bowden’s predictions with terrible clarity.

The narrator of Mr. Eck’s descent into the recesses of a bungled mission is a young soldier named Joshua Stantz. Stantz is one of six men stationed as spotters on a rooftop night guard, providing “recon in a city controlled by warlords and their clans.” The American troops are there on a humanitarian mission to deliver food and aid: “We had been sent in to restore some order to the capital and provide the people with some needed relief. … This was the last, the worst of all the cities.” It is immediately clear, however, that this will not be a story of relief: The hot, clipped tone of Stantz’s narration is more suited to a debrief; his story is told in a low rush of urgency.

Though the events that transpire are the stuff of high military drama, they arrive and are enfolded into the narrative with thudding incredulity. The scenes of attack and confrontation are quickly rendered in a casually brutal, bewildered tone of shock: “Black smoke scrolled around me. People appeared out of the smoke and then disappeared just as quickly. They were looting the bodies, fighting each other for the possessions of the dead. I fired a shot into the air. I couldn’t hear it, but I felt the weapon’s kick.”

The soldier’s story at the center of “The Farther Shore” asserts itself more pressingly as a simpler account of unimaginable heat, thirst, confusion, hunger, disillusion, loneliness, illness, and sleeplessness: Stantz is no hero, enlisting for college money, and he speaks with cold compassion of legacy soldiers such as Zeller. Mr. Eck concentrates his descriptive powers on the fine scent of human rot, the keen glimpses of personality — “When he laughed he was all teeth and slaps on the back. He would put his hand out to touch you, to let you in on the joke.” — the depressing nutrition provided by ready-to-eat meals, and the curious, Arabic labels on military-issue water bottles. Stantz’s body and those of his fellow soldiers are the seat of this particular war story. Mr. Eck’s decidedly creaturely account conjures the utter drudgery of chaos and the unfamiliar, where every new hassle is a potential catastrophe, and following protocol becomes a freighted joke.

Time and again the Army fails to account for the details, for the politics, the people, pushing forward with an unfocused eye on “success”: “They were striving for a great opening night. They were desperate for the city’s submission, desperate for perfection.”

Every man seems to get left behind at some point, and by the end of the novel Stantz is indeed an Army of one, separated from his men and then reabsorbed into another unit by sheer bloody happenstance. Mr. Eck is at work on an impressive number of ideas by this point, tugging and eliding them with a skill belied by his narrator’s impassive voice. The final act of horror and betrayal is one that threatens to strain the novel’s slender, vise-like acumen, turning its delicately cloaked metaphors of desperation, hubris, and a shape-shifting enemy out into the street. But Mr. Eck insists on the finale’s outsized symbolism as a logical extension of Stantz’s journey, using the same dulled, incredulous tone that characterizes the violence throughout, and ultimately galvanizing both the narrative and its current political reverberations: Who could believe this of ourselves, he seems to say. And yet, here we are.

Ms. Orange has written for the San Francisco Chronicle and the Toronto Globe and Mail.