Credit: Jamie Tufrey

Apprehension seized him. A dark fear of some terrible consequence gripped him and the absurdity of the experiment became crystal clear as he caught his reflection in the glossy dead stare of the television screen. But I've done this before, he realised. He didn't recall it exactly, but he remembered the fear. With a confidence that only such an impression could bring, Zane taped the electrodes to his head, pushed the PLAY button, and drank his drug-laced tea in one bold gulp.

For several minutes, eyes closed as he focussed on the day he'd found the book, nothing happened but a mild sensation of lightness. The instructions were clear. Do not activate the inducer until the compounds begin numbing your body. Zane waited for it, annoyed by the uneven buzzing of the electrical sounds in the headphones. He reached to turn it down when the compounds kicked in.

A world of understanding bloomed in a silent explosion of consciousness. Everything happening had happened before, mirrors facing mirrors. His mind looked into that endless hall and witnessed the light of creation shining from the depths of a space that didn't exist.

Free will and predestination were just names for the two facing mirrors creating the illusion of infinity. He saw his thumb flip the switch on the shock device before he realised he was about to make the decision to do so. Stars filled the darkness that rushed in from the walls.

Zane picked up the book with a profound feeling of familiarity. He remembered remembering that he'd seen it before! He didn't know if he should call that a double déjà vu or just a temporary imbalance in his memory centres.

"An oak leaf is going to …" he started to say, just as it hit the table. The sense of the familiar was matched only by his growing paranoia. That cat was looking at him again with an expectant glare. He opened to chapter one. The lines of text struck him like thunderbolts. As he started to flip to chapter two, he whispered, "You have travelled back in time, and you will do so again."

When he saw those same words on the page, he closed the book and marched straight over to the old lady to ask her what she wanted for it. She mentioned her son again before Zane drove away.

Zane picked up the book, the broken hourglass on its cover leaping out at him with terrible force. My God, how many times have I done this? he asked himself, knowing what he would see as the oak leaf fell where it always had.

Zane reached out and caught the leaf. With a smile for the cat who stared at him, he didn't even bother to open the book. Now he was ready for the final chapter. The woman, of course, mentioned her son, and this time he decided to ask.

"Where is he? Your son, I mean?"

She looked up at him with suspicion and fear. It only lasted a moment before her features settled. "Northbrook Care Centre," she said softly, then smiled a wide strange smile. "His body is there, but not his mind. He went back to his friends in college, he always goes back there." She tapped the mottled skin of her skull. Zane paid her his dollar and left, distinctly uncomfortable.

He felt cold and shaky, setting the book down. Very well. Time travel was not only real, but he'd done it several times, if his multiple recollections were accurate. The next step filled him with a revulsion and terror that far out- shadowed the first time he'd sat down in his wife's chair with the gadgets and compounds in a sequence he'd only half completed this time. He took a deep breath, and sipped his tea.

To travel beyond eight days into the past requires a dosage of chronotropic compounds and voltage levels from the inducer sufficient to cause irreversible neural tissue damage in the abandoned time line. Effects range in intensity from mild memory loss to a permanent catatonic state. Because of this, and out of a very natural fear of personality death, some travellers limit themselves to shorter journeys.

The old woman's son in Northbrook. He'd taken the long ride back, so in this time line his body remained a mindless shell.

I have to make a choice, he told himself. Is it worth risking permanent brain damage to see Emily again? He looked around the empty house, at,the forgotten drapes, the figurines he kept forgetting to dust. He wanted nothing more than to be with her again. He'd always said he would die for her, and in the darkness of her disease he'd begged God to let him die in her place. Now, it seemed, his devotion was being put to the test, not by God but by a man named Travis M. Teel.

Longer trips require proportionally more cycles to recover any memory at all. A 20-year journey requires over 7,000 cycles to achieve anything approaching full recall. That is 140,000 years in linear time. If you choose to do this, you will stay on the same event loop. You only fully remember the one culminating effective cycle. The rest of those years you're just killing time.

Zane finished building the inducer and brewing the compounds. He wondered what they would think when they found his body? Out of paranoia, he decided to burn the book. If it didn't work, there would be no point in hurting others, and if it did, he'd keep finding it at that garage sale before he burned it.

The maximum dose gave him 20 years. That would put him eleven years into his marriage with Emily. He smiled at the thought of seeing her again as the drugs took hold. Infinity yawned out, and he watched as his hand flipped the switch, as it had been doing for thousands of years. In the quiet darkness of Zane Tsien's house, a man who'd once been considered sane drugged and shocked himself into a permanent catatonic state.