"How it happened" is a very short story written by Arthur Conan Doyle, in 1918 and is part of a set of stories called Danger! and other stories.

The story is a first person account of a man who having bought a new car decides to go on his first drive as he returns one night from London. In spite of his chauffeur warning him that the gear system of the car is quite different from the older one he is willing to risk driving it for the first time at twelve in the night. His 5-mile journey passes over some very hilly terrain and has many sharp turns that he has to manage.

His drive starts smoothly but just when he starts to feel he is in control, the new gear system gets locked; the car is now hurtling down a very steep slope. On trying to slow down using the brakes even they fail and he now only has the steering wheel to control the car and manage some very sharp turns. He is successful with the first two but the last cannot be managed. The car crashes and suddenly the story takes on a new turn.

The narrator finds himself standing at a distance looking at the helpers rescue the injured chauffeur and crying out for him. He responds to their cries but don't seem to hear him and instead are  bending over something lying in front of the car.

It is evident that the narrator is dead and is looking at all that is happening in a new form. He then sees his long dead friend and exclaims in surprise that he died a long time back. The friend's response provides the final confirmation to what had happened.

“Stanley!” I cried, and the words seemed to choke my throat —“Stanley, you are dead.”
He looked at me with the same old gentle, wistful smile.
“So are you,” he answered.