Unreliable memory has long been a staple ingredient of "grip lit", since it was wielded with such panache by Paula Hawkins in The Girl On The Train and S.J. Watson in Before I Go To Sleep.
In psychological thriller Yesterday, author Felicia Yap expands this trope to an entire population. In the world of her novel, people lose their memories after a day or two, and must navigate life based on their electronic iDiaries, which they can painstakingly convert to knowledge only through rote learning.
The length of one's memories is central to one's social standing.
Genetically superior Duos, who retain two days' worth of memories, run the country, while the less fortunate Monos, able to remember only one day, form the working class.
Into this binary set-up floats the body of blonde bombshell Sophia Alyssa Ayling, once the mistress of Cambridge novelist and aspiring politician Mark Henry Evans, now mysteriously drowned Virginia Woolf-style in the River Cam.
Mark's wife Claire, a Mono languishing in an unhappy marriage with her Duo husband, wakes up feeling that "something nightmarish" happened two days ago. Her iDiary gives no clues as to what.
By Felicia Yap
Mulholland Books Paperback/ 394 pages/$29.40/ Books Kinokuniya/3/5 stars
Meanwhile, detective Hans Richardson has a day to solve Sophia's murder, lest his colleagues realise he is a Mono masquerading as a Duo.
His best clue is Sophia's iDiary, but in it, she claims that, unlike the rest, she can remember everything that has happened to her and has spent 17 years in an asylum as a result.
The premise of Yesterday is an intriguing one, but is hardly explored beyond the narrow confines of this domestic drama. A world in which people cannot remember the past would surely be drastically altered from ours, yet Yap sheds few insights on a larger scale beyond snippets of news and scientific articles.
What the novel has to recommend is a number of jaw-dropping twists, which it keeps in reserve until its final chapters when it then pulls the rug repeatedly out from under your feet with abandon.
It is let down, however, by unlikable characters with hardly any redeeming qualities. Claire is a coward. Mark is a self-absorbed philanderer whose chief regret, on re-reading diary entries of his university days as a campus cad, is his terrible prose.
Vengeful vixen Sophia has the best shot at the reader's sympathy, but there is little substance to her beneath hell-hath-no-fury rants and endless descriptions of her lingerie and heaving breasts. She cuts a Jessica Rabbit figure, just with a vicious edge.
The twists and turns may inspire thriller fans to forgive such flaws, but between unpleasant characters and an underused conceit, one is not quite inclined - as the Beatles implored - to believe in Yesterday.
If you like this, read: Before I Go To Sleep by S.J. Watson (Transworld, 2014, $15.17, Books Kinokuniya), a psychological thriller about a woman with anterograde amnesia, who wakes up every day with no knowledge of who she is and must reconstruct her memories from a journal she has been keeping.