Seize the day. Be in the present. Grasp the hour, the moment, the instant. This is the dubious advice given by outlandish Dr. Tamkin—part psychologist, part stockbroker—to poor Tommy Wilhelm. Unemployed, at the whim of his ex-wife and two children, and hurt by his proud and callous father, Wilhelm is disgusted with himself, yet forever hopeful that his suffering is purposeful. When he decides to entrust the last of his money to a mysterious commodities venture with Dr. Tamkin, he unwittingly sets in motion the most eventful day of his life. The journey that follows takes him across the length of New York City, from his hotel room at the Gloriana to the floor of the stock exchange, bringing him ever closer to "his heart's ultimate need."