Yesterday by Felicia Yap

We tend to think of memory as a library of cine recordings from our past. The playback is blurry and patchy, the colours saturated by the emotional temperature of the original moment; yet we believe that the movie we're watching is fundamentally accurate. The reality is very different, as recent brain science has revealed. Memory is constructed, and it's shifting. It's far closer to imagination or storytelling, than to the recovery of some archive recording.

This notion of the unreliability of memory is a potent theme for a novelist, so it's no surprise that so much modern fiction plays with this idea. Yet I've rarely seen this done through such a tight high concept package as Felicia Yap's debut thriller, Yesterday. Yap's premise is clean and potent. There are two kinds of people in the world: monos, who can only remember the past 24 hours, and duos, who remember the past 48. What, Yap asks, would it be like to live in such a world? To love in it? Or to kill? She also makes some cunning play with identity politics – since the duos inevitably look down on their mnemonic inferiors, the monos.

Yet the real power of the premise comes through in the confounding murder mystery at the core of the novel. Claire, a mono homemaker, struggles to piece together the past events that led to the death of a woman who appears to have been her duo husband's mistress. Hans, the mono detective masquerading as a duo, needs to solve the crime in 24 hours, before he forgets everything he's learned.

There couldn't be a more compelling ticking clock – and I burned through Yesterday. With this punchy debut, Felicia Yap has hit on a winning formula from the very start. This is a book that will keep you guessing to the very end. It’s going to be massive.