Gugu Mbatha-Raw is a charming actress who radiates poise and intelligence, which is why “Irreplaceable You” — in which her character acts in ways that are clearly self-destructive and counterproductive — rings so false. Director Stephanie Laing’s tragic love story concerns a woman who, shortly after her engagement, learns that she’s dying, a diagnosis that compels her to set out on a quest to find a new partner for her fiancé. The fatal-amour drama that ensues is too ludicrous to elicit tears, and though its cast of well-known stars may initially make it an attractive option on Netflix (where it’s exclusively premiering), its long-term prognosis is dire.
Self-possessed Abbi (Mbatha-Raw) and science nerd Sam (Michiel Huisman) have been together since a childhood class trip to an aquarium, during which Abbi — mimicking the courtship behavior of the monogamous Deep Sea Angler fish — violently bit Sam in the shoulder. Decades later, they’re living together in Manhattan and set to be married, as well as expecting a child. Their excitement, however, soon turns to horrified grief when they’re informed by physicians that Abbi is not, in fact, pregnant; the mass in her stomach is a giant cancerous tumor. While quality-of-life treatment options are available, survival is not a possibility.
Faced with such earth-shattering news, Abbi cancels her fitness club membership, starts getting chemo courtesy of a blunt-talking specialist (Timothy Simons of “Veep”), and begins attending a support group where crocheting is used as a means of coping with terminal illness. Among the unhappy kooks she encounters there are Kate (Kate McKinnon) and Myron (Christopher Walken), the latter of whom informs her that Sam will soon be entering a major “slut faze” — a comment that rocks Abbi and inspires her to start planning for her socially inept beau’s forthcoming love life without her.
When not teaching him how to do laundry, Abbi secretly creates OK Cupid profiles and interviews prospective mates for Sam — this despite the sound objections of Myron, who quickly becomes her BFF. Though Bess Wohl’s script initially posits Abbi as a Type-A personality, it all plays like a contrivance, since Mbatha-Raw comes across as far too astute to not realize she’s sacrificing her present with her paramour for a future she can’t control. That Abbi, wracked by confused, tumultuous emotions, might feel the urge to lessen Sam’s loss (via a process Myron dubs “anticipatory grieving”) is natural; that she’d waste all her time on this futile scheme seems like the stuff of outlandish movie fantasy.
Abbi’s plot eventually leads to involvement with a local photographer (Gayle Rankin), but by that point, “Irreplaceable You” has long since lost touch with reality. More frustratingly, it fails to strike a proper tone, as most evidenced by McKinnon’s performance, which exists uneasily between cartoonish and somber, and winds up feeling simply off-key. That said, the actress still fares better than Steve Coogan, whose support leader is so blandly defined that he doesn’t even merit a proper name.
Mbatha-Raw and Huisman’s cute yin-yang chemistry can’t offset the proceedings’ raft of implausibilities (like Abbi and Myron spying on Sam with binoculars), and Laing’s fondness for shooting the duo at dusk alongside the Hudson River and on rooftops which, coupled with Leslie Barber’s generic sweet-but-sad score, leads to monotony. The story of a dying woman who learns to cherish what she has while she still can, “Irreplaceable You” uses an assortment of slight incidents to impart a lesson that, from the outset, is patently obvious to everyone except the too-dim-to-be-believed person for whom it’s intended.