A short story.

It took place at midnight, on the field across the bank.
        My acquaintance stepped out of the boat, restlessly grinding his teeth. He clutched his pistol by his side.
        On the other side of the field, I saw his enemy, and his second beside him. I recognised their faces: they were decent people from the town – I had eaten and spoken with them before – and then realised that we were the wrongdoers on this night.
        I met with his second in the middle.
        “What is this all about, friend?” I said.
        “For honour,” he replied solemnly.
        “Damn this honour,” I said, but he was already walking away.
        The duellists faced each other, with pistols primed. We stood in a clearing among willow trees and a full moon stood witness to the affair.
        Then the most unlikely thing happened. The man whose second I was, suddenly cried out. He pointed to something in the enemy’s hand. I looked and there I saw a golden apple, glimmering in the light. He held it in the palm of his left hand. His pistol still hung from his waist.
        My acquaintance was mesmerised with the object. He began to shake, then splutter, then began gibbering nonsense. The golden apple had poisoned his mind. I said:
        “For God’s sake, it’s only an apple.”
        “It’s beautiful,” he sobbed. “Look at it!”
        “Get a hold of yourself.”
        I looked at the golden apple again. It shone dimly under the moonlight but I couldn’t see the point. It was hardly different to an ordinary apple.
        His enemy stood staring at us while my acquaintance fell apart before my eyes. He could not look away from the apple and collapsed onto his knees. His pistol hit the ground with a thud.
        I looked away in disgust. I never wanted this damn duel anyway. Nobody told me what its cause had been and I didn’t care anyway. I was roped into it by honour, friendship and favours I owed. Damn honour, and damn the favours that people owe. They lead people down into hell.
        There was nothing anybody could do. With every passing hour, he became less human, and more of a mess. But still he kept his eyes on the golden apple.
        Dawn broke. Still, his enemy stood, holding out the terrible object, while his second observed. My acquaintance stopped responding to questions and demands long ago. He hadn’t spoken in hours.
        Eventually the doctor arrived in his coach and asked what had happened. He had expected a winner and a loser, the loser presumed to have been killed. I pointed to the two men and said:
        “He has lost his mind at that golden apple.”
        The doctor looked over.
        “But it is just an apple.” I shook my head.
        The doctor took out his tools and examined my acquaintance, still crumbled on the grass. After a moment, it was decided that he needed to go to hospital. We had to take the coach, the long way to the town. As we pulled away, leaving our boat behind, the enemy still remained, holding the golden apple. He stood as still as a statue under the morning light. I never saw him again.
        My acquaintance never recovered. We took him to hospital, where the hallucinations began. Then his madness. The doctors diagnosed him with a stroke. High blood pressure, they said. Terrible in stressful situations.
        I visited him often, then less over time. Whenever I visited, he would always ask me about the golden apple. I told him I hadn’t seen it again, but he refused to accept this and would become angry. I began to be more evasive in my answers. Eventually I stopped visiting him altogether. His instability was beginning to infect me. It doesn’t take much, does it, to break a man. Especially if, in a clearing, at midnight, under a moonlight sky, a mind cannot unfix itself from a distraction.