Serena Frome, the main character of Ian McEwan’s new novel, “Sweet Tooth,” reads constantly, speeding through two to three novels per week. McEwan presents his readers with extracts from those novels: thus in reading “Sweet Tooth,” one gets much more than just Serena’s story. We read what she reads too, sifting through layers of narration to find what is true in all of the fiction. The most intriguing part of McEwan’s new work is the slippery sense that no narrator can be trusted as the reader tries to separate Serena’s story from the fiction that surrounds her. By weaving story upon fictional story, McEwan manages to trap his reader in a web of meta-narration that is at once exciting and unsettling.

“I was the basest of readers,” Serena says in one such metanarrative moment. “All I wanted was my own world, and myself in it, given back to me in artful shapes and accessible form.” What Serena wants is to see herself in a fiction story, which is exactly what a reader of McEwan’s novel gets; we read versions of Serena in the stories written by Tom Haley, another character. Serena meets Haley while she is working on a mission for the Civil Service, a subset of the British parliament similar to the C.I.A., in London. Serena is chosen for her enormous range of literary knowledge to follow and support the work of Tom Haley. She eventually falls in love with Haley, but only after learning to love his fiction. Here, McEwan decides that the reader should get a taste of Haley’s writing with Serena, and so he weaves Haley’s writing directly into Serena’s narration. Haley’s words are in italics next to Serena’s interpretation of the story so that both McEwan’s and the fictional Haley’s words are seamlessly fused in the novel.

When Serena first encounters Haley’s work, she is struck by how closely she identifies with the characters in the story. While reading, she pauses on an asterisk in the middle of Haley’s story to imagine the directions it might take. “I stared into it to prevent my gaze slipping down the page and revealing the author’s next move,” Serena says. Her consciousness is our own; until Serena decides to move on and read the rest of the story, we will not know the ending. Serena has an unbelievable amount of control over our knowledge, and she chooses to tell only certain parts of her story, leaving the rest to the bits of Haley’s fiction that intrude into her voice. At this moment of introspection, when Serena stares at the asterisk, McEwan gives his readers a pause to consider the changeable relationship between details in Haley’s story and Serena’s own untrustworthy voice. Then, both Serena and McEwan dive back in, immersing the reader back into another level of storytelling and eliminating the brief reprieve in the confusing mix of realities.

When Serena thinks about herself, she judges her own actions as harshly as if she were another narrator, again adding to the unsettling nature of the narration. She makes note of her own dependency on others, her confusion while working at the Civil Service, and her insecurities about being qualified for her job. When Serena is at work, she is constantly unsure of whom to trust. Her colleagues are tittering office girls with more brains than they let on; girls who are perfectly willing to reveal Serena’s unprofessional approach to her assignments.

“Sweet Tooth” is set in the midst of the cold war in England, an already paranoid setting which compliments the odd nature of the multi-voiced narration. Serena navigates her way through the British Civil Service office, agreeing to work on a case called Sweet Tooth. Her mission is to encourage the writing of Tom Haley, a writer chosen by the British government for his anti-communist fiction. She goes undercover, self-consciously dropping lies as she provides money from the government to support Haley while he writes what is supposed to be the next great pro-capitalist novel for the good of democracy. But she fails, fumbles, and embarrasses herself by the end. Up until the final pages of the novel, McEwan maintains the curious metanarrative, and the mixing of Serena’s own story with the words of Tom Haley, but McEwan’s conclusion stifles that unique narration.

“No single element of an imagined world or any of its characters should be allowed to dissolve on authorial whim,” says Serena earlier in the novel. At the time, Serena meant to direct the opinion at Haley’s writing when one of his fiction stories ended by revealing another character whom had been “writing” the story the whole time. But the distaste for authorial whims might also be applied to the reader of McEwan’s novel, and not merely the story-within-the-story that Serena recounts in her narration. The end of “Sweet Tooth” casts the whole proceeding story in a new light, and one that is perhaps too kitschy and unfulfilling. If the best parts of the novel are McEwan’s interesting fusion of narrative voices, he negates his interesting style in the space of a few pages.

McEwan devotees will see a similarity between the endings of “Sweet Tooth” and that of “Atonement,” but McEwan does not pull off “Sweet Tooth” as gracefully as he finished “Atonement.” McEwan’s precise and piercing language remains in his most recent novel, but the structure and narrative choices do not hold all the way through to the end.

—Staff writer Virginia R. Marshall can be reached at virginiarosemarshall@college.harvard.edu