Lock Up the Darkness by Leia King inaugurates its narrative amidst the shadowy fringes of genre fiction, flirting audaciously with elements of mystery, fantasy, and psychological thriller. The book, which might best be described as a journey into the human psyche's darker corridors, pits its characters against not only external evils but also the labyrinthine complexities of their inner lives.

The story unfolds in the grimly picturesque town of Duskhollow, a place as enigmatic as it is foreboding. King's prose effectively captures the essence of this eerie backdrop, binding the setting so intrinsically to the plot that Duskhollow itself emerges almost as a character in its own right. The novel's protagonist, Elaine Marrows, is a detective with a haunted past, a theme common yet unfailingly potent in noir fiction. However, King's treatment of Elaine's backstory—involving the mysterious disappearance of her brother decades ago—eschews cliché by interweaving her personal torments with broader, more existential inquiries.

The primary narrative arc involves Elaine's investigation into a series of disappearances eerily similar to her brother's unresolved case. As Elaine delves deeper into the mystery, the boundaries between the supernatural and the psychological blur, leading her—and the reader—into a disorienting mesh of supernatural occurrences and horrifying realizations. This interplay is one of the novel's strongest suits, deftly handled by King, who balances the scales between suspense-filled supernatural elements and the all-too-human capacity for psychological terror.

A noteworthy aspect of Lock Up the Darkness is its robust character development. Elaine, as the centrepiece of this elaborate chess game, is meticulously sculpted. King does not merely present her as a stereotypical hardened detective; rather, she is imbued with vulnerabilities, regrets, and a palpable desperation that makes her relatable. The secondary characters, too, are far from mere plot enhancers. Each supports the thematic infrastructure of the novel, from Elaine’s skeptical partner, Detective Mark Jenkins, who brings a necessary grounding to the sometimes ethereal narrative, to the enigmatic Mrs. Clairmont, whose cryptic prophecies drive much of the plot's momentum.

The dialogues in the novel deserve special commendation. They oscillate seamlessly between sharp, realistic exchanges and more philosophically laden reflections, mirroring the dual existential and corporeal battlefields the characters navigate. This duality not only enriches the narrative but also deepens the readers’ engagement with the characters' struggles.

In terms of pacing, King manages a steady escalation of tension, avoiding the common pitfall of premature reveals that could sap the story of its mystique. The carefully constructed climaxes—a series of crescendoing revelations—culminate in a gratifying yet unsettling resolution that challenges the limits of conventional happy endings. Here, the resolution feels neither contrived nor predictable, a testament to King's skill in storytelling.

From a stylistic standpoint, King’s language is both evocative and precise. Her descriptions of Duskhollow bring the town to life, cloaking it in an atmosphere thick with a sense of impending doom. The narrative is adept at maintaining a balance between verbose descriptions and a tighter, action-driven language that keeps the reader’s attention riveted to the page. Moreover, the integration of thematic elements like darkness not only as a physical absence of light but also as a metaphor for the unknown and the unconscious is seamlessly done, adding depth to the narrative layers.

However, the novel is not without its minor flaws. At times, the integration of supernatural elements feels somewhat forced, risking the cogency of the plot. Additionally, some of the psychological explorations, though compelling, border on the didactic, potentially alienating readers less inclined towards introspective narratives.

Overall, Lock Up the Darkness is a compelling tapestry of mystery, suspense, and psychological exploration. Leia King succeeds in crafting a novel that is not only thought-provoking and deeply atmospheric but also provides a genuine emotional odyssey for the reader. It is a recommendable read for those who are fans of psychological thrillers with a supernatural twist and appreciate narratives that provoke contemplation about the darker facets of human nature. The book is an exemplary instance of how genre fiction can transcend its confines, offering insights that are both universal and profoundly personal.