Much of this centered around his memories of his wife Francis. His drug use (both recreational and prescribed by doctors) caused him to drive her away, and sent his marriage into ruins. There were two scenes that were telling. The first was after he was beaten by the police in front of a club he was playing, after returning home, he tells Taylor to stop dancing. She is outraged by this, but eventually does so, to her eventual regret. This would seem to have been the beginning of the end of their marriage. But there was a hint at the catastrophe to come earlier in the story, after Davis and Taylor made love. She gets out of bed and, in post-coital ecstasy, begins to dance. Davis watches her a moment, then gets up, goes to the other room, picks up his trumpet and begins to play. The surface interpretation of this is that her dancing inspired this piece of music. But it’s possible that his gesture was a desire to escape any aspect of her that wasn’t focused on him. He couldn’t handle Taylor having or being something on her own.
In the end, while Davis clearly had no fear of man or beast, it was the fear of the uncomfortable truths about himself that drove him into darkness.
But the story has a happy ending. Expect no spoilers here. Suffice it to say that he emerges from his Dark Night of the Soul into a new inner and outer realm of both renewed musical genius, and something resembling inner peace.