Abhimanyu Saliyan is a Special Director with India's Intelligence Bureau — the kind of man other people call when something threatens to go very wrong. On the morning of January 1st, 2050, something impossible happens to him instead: a craft not of this Earth pulls him from a lonely hillside road and into a conversation that will unmake everything he thought he understood about time.

The being who calls himself Captain Ace has crossed dimensions to find him. Somewhere on Earth's own timeline, a bomb is about to detonate on a crowded train — and a boy who could one day change the course of world peace is sitting in the blast radius. There is exactly one way to stop it: send Abhimanyu back. Not years. Not months. One day.

Yesterday.

What follows is a twenty-four-hour reckoning — with hardened terrorists holding a kidnapped woman hostage, with the man who once took everything from him, and with a wormhole tunnel that offers no second chances. But the deeper Abhimanyu goes, the more he realises this mission was never only about saving strangers. Somewhere in yesterday, in tomorrow, in the space between them — Anupama is still waiting.

A time-travel thriller grounded in real physics, real grief, and one impossible second chance — for readers of hard science fiction who also want a heart.