Some people would argue that forbidden love stories are the only love stories worth telling. The people who would argue that are probably not the kind of people you should date. Sure, a love story can be compelling if parents or society or circumstances deny the lovers from their right to be happy. But not every transgression is a welcome one, and not every love story is innocent.

The titular narrator of Jennifer Tseng’s novel Mayumi and the Sea of Happiness believes that she is in love, and she believes passionately in the love story she’s telling. You get the sense that if her love story were more banal — if society didn’t disapprove — she would probably not be as transfixed as she is. But by her own account she is a Woman In Love, a soldier in the war of the heart, and so she’s granted permission by some higher power (not necessarily God so much as Venus) to spit in the face of what other people think.

The problem is that Mayumi is a married 41 year-old mother of one, and her lover is a 17 year-old boy. Mayumi works as a librarian on a small island off the coast of Massachusetts. She meets her lover (she refuses to tell us his name) in the library where she works. It’s not love at first sight so much as a blissful explosion of lust in Mayumi’s heart. Her husband, Var, has been unemployed for so long he’s practically a ghost in his own house. In fact, readers should be forgiven for forgetting Var exists for much of Happiness. Mayumi is not so much an unreliable narrator as a distinctly reliable one, because her focus is always on herself. Barring the object of her infatuation, unless Mayumi’s actively speaking to another character, they basically disappear from her world.

Mayumi and the Sea of Happiness is a book-length refutation of Donne’s claim that “no man is an island.” In fact, Tseng seems to be arguing, we are all islands, alone in our own seas. On her idyllic little island, Mayumi doesn’t pay much mind to the news, or to anyone on the mainland. And even on the island, she is alone and apart from everyone, assessing the world around her with a cool eye, soaking in the thrill of her own secret.

This is a book that basks in literary tradition, a narrative told by a woman who employs literary criticism as a way to comment on her own situation. As Mayumi attempts to seduce the young man during his library visits, the book that she most identifies with is Ethan Frome. Later on, in a breathtaking moment of hubris, she convinces the young man’s unsuspecting mother to check out a copy of Lolita. Before that, the mother reads Crime and Punishment, a story which finds a thin echo in Mayumi’s occasional bursts of guilt.

And Mayumi finds empathy in other, strange places, too. As she works on her seduction plot, she finds herself identifying with street harassers:

They were the questions that cut with dizzying speed to the chase: Are you available? May I kiss you? May I make love to you now in the stacks? I gained new respect for those men who thought little of posing such questions on a regular basis and to complete strangers. The very men I once felt assaulted by now struck me as boldly in touch with Fate and the Implications of Time. If not now, when? The bomb of time was ticking!

The “happiness” of the title is not ironic; for much of the book, Mayumi is ecstatically happy. She understands that her desires and actions are wrong, and that she would suffer grave consequences if anyone found out about her affair, but she feels as though she has no choice; it’s beyond worth it. It’s not even in question.

Still, she’s occasionally overtaken by a desire to confess, but even that desire feels more like a need to brag, to have another adult, one of her peers, understand what she’s done.

…I had never known how very good I was until I became very bad. When one transgresses one does not so much inhabit a different body as wear a different coat. One remains oneself for the duration — the conscientious, law-abiding librarian slips into the criminal’s leather coat and the two magically coexist. And yet one cannot remove the coat without implications. It is no ordinary coat. One is changed by wearing it, even if, in the end, one takes it off.

Because Mayumi wears her secret transgression so boldly, other islanders somehow sense it and begin to confess their own sins to her. “Thierry Lambert’s wife was the nanny for whom he had left his first wife, Joe Fischer had been banished from the priesthood for his love affair with an altar boy…” Mayumi seems unmoved, even unimpressed by those admissions. So what?, she seems to say, I’m fucking a seventeen year-old.

Those expecting a typical crime and punishment story, or those who need to see the scales balanced after every transgression, will likely be unsettled by Mayumi and the Sea of Happiness. But those who enjoy existential examinations of transgression will find so much to enjoy here. This is a confession that reads like an exultation, and Mayumi’s gleeful admissions will likely keep the reader turning pages at the kind of speed that inspires papercuts.

Mayumi is a keen observer of her own actions, but her blind spots are plentiful and huge. She cannot seem to reconcile her illicit affair with her clingy relationship with her own daughter, for example. And her jealousy is a rabid beast, striking out at inopportune times and at innocent victims. A mind may be an island, alone in a dark sea, but it can never fully comprehend its own topography. Sometimes a confession is the only way we can fully understand the nature of the crimes that we’ve committed.