At the beginning of McEwan's novel, the narrator looks back to the day when he and his girlfriend, sharing a picnic, are interrupted by a hot-air balloon landing in the field. The pilot of the balloon is in trouble: The pilot must have been half way out of the passenger basket as it touched the ground. His leg had become entangled in a rope that was attached to an anchor. Now, as the wind gusted, and pushed and lifted the balloon towards the escarpment, he was being half dragged, half carried across the field. In the basket was a child, a boy of about ten.

The narrator and three other people see the danger, and run to help.Together with the balloon pilot, they each grab hold of a line, and so keep the balloon from rising into the air. Then, amidst much confusion, there is a gust of wind, the pilot loses his grip, and the balloon rises into the air with four people holding on desperately. The young boy is still in the basket. For a few seconds, all four hold on, and then ...

"I didn't know, nor have I ever discovered, who let go first. I'm not prepared to accept that it was me. But everyone claims not to have been first. What is certain is that if we had not broken ranks, our collective weight would have brought the balloon to earth a quarter the way down the slope as the gust subsided a few seconds later. But as I've said, there was no team, there was no plan, no agreement to be broken. No failure. So can we accept that it was right, every man for himself? Were we all happy afterwards that this was a reasonable course? We never had that comfort, for there was a deeper covenant, ancient and automatic, written in our nature. Co-operation---the basis of our earliest hunting successes, the force behind our evolving capacity for language, the glue of our social cohesion. Our misery in the aftermath was proof that we knew we had failed ourselves. But letting go was in our nature too. Selfishness is also written on our hearts. This is our mammalian conflict---what to give to the others, and what to keep for yourself. Treading that line, keeping the others in check, and being kept in check by them is what we call morality. Hanging a few feet above the Chilterns escarpment, our crew enacted morality's ancient, irresolvable dilemma---us, or me.

"Someone said me, and then there was nothing to be gained by saying us. Mostly, we are good when it makes sense. A good society is one that makes sense of being good. Suddenly, hanging there below the basket, we were a bad society, we were disintegrating. Suddenly the sensible choice was to look out for yourself. The child was not my child, and I was not going to die for it. The moment I glimpsed a body fall away---but whose?---and I felt the balloon lurch upwards, the matter was settled, altruism had no place. Being good made no sense. I let go and fell, I reckon, about twelve feet. I landed heavily on my side, I got away with a bruised thigh. Around me---before or after, I'm not so sure---bodies were thumping to the ground.

"By the time I got to my feet the balloon was fifty yards away, and one man was still dangling by his rope. In John Logan, husband, father, doctor and mountain rescue worker, the flame of altruism must have burned a little stronger. It didn't need much. When four of us let go, the balloon, with six hundred pounds shed, must have surged upwards. A delay of one second would have been enough to close his options. When I stood up and saw him, he was a hundred feet up, and rising, just where the ground itself was falling. He wasn't struggling, he wasn't kicking or trying to claw his way up. He hung perfectly still along the line of the rope, all his energies concentrated in his weakening grip. He was already a tiny figure, almost black against the sky."

Tom Slee, 2004