Before Martha Finley had completed the first six titles of The Elsie Books in 1876, she began a new series based upon the Dinsmore's Midwestern relatives, the Keiths. The resulting seven-book series, The Mildred Series, introduces Mildred Keith, their sixteen-year-old daughter. Her father, a lawyer by trade, had moved with his wife and eight children from Ohio to the frontier of Indiana in the 1830s (not unlike Martha Finley's identical journey as a girl with her family). At the end of the first book, Mildred becomes very ill with a fever and is slow to recover. Arthur Dinsmore Sr., Elsie's grandfather, travels from Roselands, his home in the East, to visit the Keiths. While there, he suggests that the southern climate at Roselands may be beneficial to Mildred's health. This is followed by the death of Elsie's guardian in Louisiana. Mildred travels with Arthur Dinsmore to visit Elsie at Viamede. In this way, The Mildred Books fill the reader in on some of the events of Elsie's early childhood before the Elsie series opens. Martha Finley has woven the characters of the two series in and out of her stories to fill in some of the sequential gaps in the plot lines of her early Elsie stories and to provide some further depth to her characters and their relationships with one another. In this way she enriches the Elsie stories that have thrilled girls for more than 130 years. Sixteen-year-old Mildred moves with her father, mother, and seven brothers and sisters from their home in Ohio to the frontier of Indiana, and Mildred's maiden aunt, Wealthy Stanhope, travels west with them. Horace Dinsmore, Elsie's father, pays a visit to his cousin, Marcia Keith, and her family in Indianabefore departing on a long trip to Europe, and sadly, the entire Keith family is stricken with ague.

Before Martha Finley had completed the first six titles of The Elsie Books in 1876, she began a new series based upon the Dinsmore's Midwestern relatives, the Keiths. The resulting seven-book series, The Mildred Series, introduces Mildred Keith, their sixteen-year-old daughter. Her father, a lawyer by trade, had moved with his wife and eight children from Ohio to the frontier of Indiana in the 1830s (not unlike Martha Finley's identical journey as a girl with her family). At the end of the first book, Mildred becomes very ill with a fever and is slow to recover. Arthur Dinsmore Sr., Elsie's grandfather, travels from Roselands, his home in the East, to visit the Keiths. While there, he suggests that the southern climate at Roselands may be beneficial to Mildred's health. This is followed by the death of Elsie's guardian in Louisiana. Mildred travels with Arthur Dinsmore to visit Elsie at Viamede. In this way, The Mildred Books fill the reader in on some of the events of Elsie's early childhood before the Elsie series opens. Martha Finley has woven the characters of the two series in and out of her stories to fill in some of the sequential gaps in the plot lines of her early Elsie stories and to provide some further depth to her characters and their relationships with one another. In this way she enriches the Elsie stories that have thrilled girls for more than 130 years. Slow to recover from her bout with ague, Mildred joins her uncle, Arthur Dinsmore Sr., on a trip by rail and steamer to the Dinsmore home, Roselands, to take advantage of the southern climate. Mildred befriends the governess at Roselands and is befriended by sweet Violet Travilla, mistress of Ion and mother toEdward Travilla. When Elsie's guardian dies, the motherless Elsie is brought to Roselands while her father is still in Europe. Meanwhile, Mildred struggles to remain firm in her faith and endures the heartbreak of loving Charlie Landreth, someone she cannot marry.

Mildred's stay at Roselands draws to a close, and she is torn between her beloved home in Indiana and her newfound friends and family. She has blossomed into a beautiful young woman and must discourage the advances of not one, but two suitors, for she still loves Charlie. When Elsie recovers from a life-threatening illness, she visits the Keiths in Pleasant Plains with her father. After years of separation, Mildred and Charlie Landreth reunite to find all of the obstacles to their love now removed, and they marry.

Charming Stories That Have Stood the Test of Time Mildred and Charlie Landreth have become the proud parents of a baby boy, Percy, and have settled into quiet domestic life. When they receive an invitation from cousins Horace and Elsie to visit the Oaks, near Roselands, they travel there with Mildred’s youngest sister, Annis, to spend the winter in the sunny South. Their days are filled with family gatherings, visits with friends, pony rides, and walks through the countryside, and as Christmas approaches, they send fond greetings to their loved ones back home. Annis and Elsie make time for their studies, and Elsie—whose kind and obedient nature touches all around her—learns important lessons about obedience, trust, and guilt. As winter ends, Mildred, Charlie, Annis, and Percy bid farewell to their relatives and begin the journey back to their home in Pleasant Plains, Indiana.

The Landreths and Annis meet Aunt Wealthy in Philadelphia on their way home from the Oaks and complete their journey with her at their side. Mildred and Zillah, her sister, welcome daughters into their homes and learn much about raising children. Don and Rupert, Mildred's brothers, heed the call to "Go West, young man!" When they are attacked by Indians, the Keith family mourns their likely loss but rejoices in the knowledge that if they are dead they are in a far better place with the Lord.

The Landreths harbor a family of fugitive slaves. The family fears the oncoming civil war and the possibility of sending fathers and sons, brothers and cousins off to fight. Rupert, Cyril, and Donald Keith, Wallace and Stuart Ormsby, and young Percy Landreth are eager to defend the Union they revere and love, but they are also anxious to return to family and friends at home.

Young orphans Ethel, Blanche, Harry, and Nannette Eldon have suffered much since the loss of their parents—their British father after a prolonged illness and their mother suddenly over the shock of her husband's death. Now these youngsters are sent across the Atlantic to live with their uncles in Philadelphia. Ethel, who is eager to do her share to support her brother and sisters, takes a job running a shop, and she and Blanche become engaged to cousins Stuart Ormsby and Percy Landreth. The boys bring their brides home to Pleasant Plans, and Mildred gains a daughter.