A dazzling new novel of friendship, identity and the unknowability of other people  – from the international bestselling author of Home Fire, winner of the Women's Prize for Fiction

Sometimes it was as though the forty years of friendship between them was just a lesson in the unknowability of other people.

Maryam and Zahra.

In 1988 Karachi, two fourteen-year-old girls are a decade into their friendship, sharing in-jokes, secrets and a love for George Michael. As Pakistan's dictatorship falls and a woman comes to power, the world suddenly seems full of possibilities. Elated by the change in the air, they make a snap decision at a party.

That night, everything goes wrong, and the two girls are powerless to change the outcome.

Zahra and Maryam.

In present-day London, two influential women remain bound together by loyalties, disloyalties, and the memory of that night, which echoes through the present in unexpected ways.

Now both have power; and both have very different ideas of how to wield it. Their friendship has always felt unbreakable; can it be undone by one decision?