In New York a young man has his "day of days", when in twelve short hours he breaks the bank at a gambling-house, is held up for his winnings at the pistol's point, escapes during a raid, enters a private residence, saves its mistress from murder at her husband's hands, and plays no small part in events at a fashionable masquerade ball and in the deadliest dive in New York--all of which has its bearing on the plot of the story in which little Mr. Sybarite saves the girl he loves from the machinations of a rascally trio.