THE SEX LIVES OF SIAMESE TWINS

A rage-fueled gym rat enters into an abusive, symbiotic relationship with an overweight artist in a brash, decidedly Welsh-ian study of body image and media.

Scottish cult legend Welsh (Skagboys, 2012, etc.) takes a detour to Miami Beach for this novel, in which lead narrator Lucy puts her well-machined physique to good use early, stopping a gunman taking aim at two guys on a highway. A witness, Lena, records the incident, making Lucy into a momentary celebrity. But Lucy’s dreams of parlaying her semifame into a Biggest Loser–style reality show die quickly: The gunman turns out to have been aiming at alleged pedophiles, complicating the media narrative, and Lucy’s adrenalized demeanor alienates her would-be TV partners. Lucy does everything in a fury, from emails to back-alley sex with men and women she picks up in clubs, suggesting that the friendship she starts with Lena won’t go well. Indeed, it goes badly in a humanity-at-its-worst kind of way. What begins as Lucy’s boot-camp–style fitness plan for Lena, a brilliant artist unlucky in love, turns into a captivity tale that explores the body and our obsession with others to a disarming, at times grotesque degree. (The title refers to a subplot involving a media circus about conjoined twins.) Welsh writes intelligently in two registers—blown-gasket Lucy and subdued, self-pitying Lena—and he uses those differing tones to ingeniously explore how self-image influences our perceptions of others. The flaw is that the novel’s opening sense of emotional subtlety with both characters degrades into something more farcical, as the women become more blunt representations of fat vs. thin, punctuated with Grand Guignol splashes. Welsh isn’t given to hollow provocation, but the depth of his social critique is undermined by his more absurd plot turns.

A sometimes pleasurably over-the-top, sometimes simplistic proof that physical and mental health aren’t always intertwined.