John Douglas divorces his wife, taking custody of their son Kenneth and leaving her with their little daughter Kathleen. Mrs. Douglas dies in poverty, and Kathleen falls in with crook Jack Baggot and his wife, who teach her how to pick pockets.

Mildred Vandeburg, an heiress who devotes her time to a hospital that she has built in the slums, breaks her engagement to her fiancé, T. Huntington Forbes, because Forbes is only interested in horses and sports. Meeda Jones, a nurse employed in Mildred's hospital, is married to a criminal named Spike, who steals some jewels and convinces his brother Dan to fence them for him. When Dan is killed as the police try to arrest him, his wife dies of shock, leaving their baby girl homeless. To help the baby, Mildred decides to take her to Forbes's home, where she informs her former fiancé that there is a "lady in the library" waiting for him.

In March 1916, Pathé released a short feature entitled Little Mary Sunshine, starring a four-year-old Marie Osborne. This was one of the first features ever directed by King and it was so successful that Pathé asked the original production company, Balboa, for five more features with the same child wonder. All were produced during the second half of 1916, and only three of them survive today – one being Twin Kiddies, which shows the amazing progress King had made since the first film in the series. Of course, the story is thin, the ending quite abrupt, and the opening sequences rather long. Yet, the direction is much more subtle, alternating between shots of different size, suggesting that King was mastering the art of composition.

Half-breed Nor is loved by French Canadian Jacques but when they quarrel, she meets Englishman Cedric Ralston who has been jilted by his fiancée Margaret for his elder brother, Lord Ralston. Later, Nor and Cedric are married, but on the day of their wedding, Cedric hears of his brother's death, and he goes to England, taking Nor. Unhappy she realizes Cedric’s heart belongs to Margaret and Nor returns to her mountains and to Jacques.

Joyce Tolliver, whose nickname is Muggsy, plays baseball, fights and swears with boys, and is severely punished by her elders. When she grows up, she is disguised as a boy, and sent to live with a wealthy old uncle, Leslie Bolton, who hates women. Her ruse works perfectly until she falls in love. When Bolton e discovers that his supposed nephew is really his niece, he orders her out, but after he realizes that he cannot get along without her, he sends for her to return.

Jilted on her wedding day, Maud Wainwright becomes a confirmed man-hater. Homesteading in the Southwest, she ignores the attentions of both bandit "Three Gun Smith" and Sheriff Steve Kennedy. When Smith's gang accidentally knocks over Maud's cabin, the men take her to Smith's cabin while they rebuild her dwelling. There, Maud discovers a mail pouch and believing that it was stolen by Smith, reports him to the sheriff, who persuades her to assist him in arresting the bandit. After Smith is captured, Maud discovers papers that prove he is actually a secret service agent and that the sheriff is the real bandit. Riding to Smith's rescue, Maud prevents him from being lynched at the hands of vigilantes and then proclaims her love for him.

Little Sallie O'Brien, who sells newspapers on the city streets, is adopted by Bridget Cassidy, the landlady, when her mother dies. Mrs. Cassidy treats the child cruelly, but soon the wealthy James Wilson befriends Sallie and takes her into his home. Sallie is befriended by Wilson's son Richard, but his daughter Marjorie dislikes the impish little girl.