The basic gist of the story revolves around a small family, whose mother and father are always wanting more money. The children can sense this, and in a misguided attempt to win his mother's love, the little boy, Paul, tries to get money for his mother. He actually succeeds quite well; through riding his rocking horse, he is able to glean the names of winning horses in the horse races. The gardener and uncle discover his talent, and help him invest money in the races. He wins a lot for his mother, and secretly gives it to her. She just wastes it, however, and doesn't love her son any more. His rocking-horse riding becomes more intent and feverish, and eventually sends him into illness and death. His mother realizes, too late, what he had been doing.
I would highly recommend reading the story, if you haven't already. It is an engaging read, filled with symbolism and meaning. I hope that helped; good luck!