There were four of them, Betty Nelson, or the “Little Captain” as the girls often called her because she had such a decided talent for knowing just the right thing to do at just the right moment, was eighteen, dark-haired and dark-eyed.  She had a fund of vitality and more than her share of sense and good judgment—­ all of which went toward making her what she was, the most popular girl in Deepdale.

Grace Ford, tall, slender and willowy, was almost the same age as Betty, but that fact and her love of the outdoors were the only things she had in common with the “Little Captain.”  Her father, James Ford, was a lawyer, and her mother, Mrs. Margaret Ford, a rather dressy lady who spent a good deal of her time at clubs, was quite a figure in the society of Deepdale.  However, all through the war Mrs. Ford had worked with an untiring enthusiasm for the “cause,” a fact which had made her many more friends than her social popularity could ever have done.

Next in the little quartette came Mollie Billette.  Mollie was seventeen, French-American, and impulsive, with a quick temper that made more trouble for herself than for any one else.  She and Betty were alike in their splendid vigor and vitality.  Mollie, or “Billy” as she was sometimes called by her chums, had a very lovely widowed mother and an extremely mischievous young brother and sister, Paul and Dora (nicknamed “Dodo"), who were twins and six.  Although the twins were pretty nearly always in trouble, they were really adorable children, whom everybody loved.

Amy Blackford, shy, sweet, pretty, completed the quartette.  There had been a mystery about her past which had recently been cleared up, and it may have been this mystery that caused the girls to treat her with a little more consideration and gentleness than they did each other.  Her guardian was a broker in the city who knew very little of the past except through letters.

The four boys who were close chums of the girls and had added to the interest and excitement of more than one of their adventures were Allen Washburn, who was very much interested in Betty, and in whom Betty was very much interested; Will Ford, Grace’s brother, who had carried Amy Blackford’s picture all through the war; Frank Haley, Will Ford’s closest chum, and Roy Anderson who had not much distinction of any kind except that he was “lots of fun” and a chum of the other three boys.

In the first volume of this series the girls went on a camping and tramping tour, tramping for miles over the country and meeting with many adventures on the way.

Later they had more fun at Rainbow Lake, in a motor car, in a winter camp, in Florida, at Ocean View, then at Pine Island where the girls and boys together had cleared up a mystery surrounding a gypsy cave.

Later the girls and boys found themselves caught in the meshes of the great war, as many hundreds of thousands of others had been.  The boys responded eagerly to the bugle call, and the girls, too, were eager for Army service and finally went to a hostess house at Camp Liberty.  Though the girls had never worked harder in their lives, they found that the task had a stirringly romantic side as well.