Mary Boyne, who made shirts at four dollars a week, had no place for love in her life - only despair and hate for the son of the man who had plunged her family into deepest distress. Peter Kenwitz loved Mary, but because he was a mathematician and a pessimist by trade, his love was as hopeless as her chance for happiness.

The one was a venturer - the other an adventurer - the one a man who wanted to see adventure, but who had never been beyond the city limits - the other a man who had seen adventure in all parts of the world, and who assured the venturer that things were just as monotonous every place in the world as in the city. So they met, each seeking for the unconventional, on a New York street, and dined together as men out of luck, with two cents between them - and still nothing happened. They both had credit at the hotel. Then into their lives came the feminine influence - a sweet girl who lived in a house which was irrevocably a household. The adventurer hesitated - he had yet to satisfy his longing for the incalculable. Suddenly love changed the venturer into an adventurer, and settled the adventurer into a venturer.

When his sweetheart jilts him, wealthy James Armitage leaves his family estate in the hands of attorney Samuel Bordman and heads for Burma. Six years later, Armitage discovers that his former girlfriend has just become a widow, thus he sails back to America in hopes of rekindling the romance.

Dr. Hugh Loring, whose hobby is heredity, has evolved the theory that physical or mental peculiarities of children reveal the parents. The doctor's intense desire for children is only equaled by his wife's aversion. On the occasion of the doctor admonishing his wife for being friendly with an admirer she leaves him, and when her child is born she swears Ruth Carden, an employee of her husband's, who has accompanied her, to secrecy, so that she may keep from the doctor his greatest joy. Mrs. Loring dies, and Ruth returns to the doctor's office, leaving the child in the care of the nurse. Three years later the nurse finds it necessary to give up the child, and the doctor, who has fallen in love with Ruth, is stunned, for he believes that the child is hers.

When Alice Winton's brother embezzles funds belonging to his employer, Benjamin Graves, a promoter of worthless mining stock, she saves him from arrest by signing over to Graves a hefty promissory note. Later Graves deliberately wrecks the mining company in which Alice's invalid father has invested his money, and the shock from the resulting bankruptcy, kills him. Alice marries Robert Burton, a noted criminologist who believes in the theory, "once a thief, always a thief," and the couple takes up temporary residence with District Attorney Jeffrey Miller. In Miller's safe are incriminating documents concerning Graves's illegal activities, and Graves, knowing of their existence, blackmails Alice into stealing them by showing her some compromising love letters to which he has forged her name.

After Mary Allen drops a blood-stained knife, Judge Robert Craigin's dead body lies next to her. Mary secures a secretarial position with Judge Bruce Craigin, the dead man's younger brother. Professor Galt, a criminal psychologist, and Detective Hooker believe that Mary committed the crime. Craigin and Mary fall in love and are married. Galt persuades Craigin to let Mary furnish their new home because a clue to the solving of the murder is the artistic furnishings of the room in which the murder victim was found. The similarity between the decor of the house and the crime room convinces Craigin that Mary murdered his brother, but Thomas Gray confesses to the crime. He had been in the room waiting to avenge his wife's wrongs on Craigin. When Craigin attacked Mary, she lifted her paper-knife and fainted, and Gray killed Craigin, leaving the murder weapon in Mary's hand. Mary and Bruce find happiness together.

Jimmy Ryder, full of dreams of conquering the world, marries Pidgie and together they go to the city to make their fortune, but fortune refuses to smile on them and they're reduced to living in poverty.

Jacob Spraggins, veteran general of a breaker-boy-to-multi-millionaire campaign, is driven by a troublesome conscience into the ranks of the amateur Haroun al Raschids, who infest Bagdad-on-the-Subway.