The Secret of St. Gabriel's Tower is the first novel of a proposed trilogy involving three eleven year-old best friends who live in a fictionalized "colored" town in Northern California. The date is the late 1920s. The girls' names are Amber Walker, Robyn Jones and Jessica Johnson. They are so close that one rarely sees one without the others to where they are nicknamed, The Triplets, by the town's people.

Ruthie Joan, one of The Triplets' classmates and the only one in the TriCove area to contract polio, does not return home one day after she accepts a ride in a car with a boy from another town. What happened to Ruthie Joan? Was she kidnapped? Did she fall over one of the many cliffs that front the town of Poplar Cove near the Pacific Ocean? Did she run away? Who better to find out what happened to Ruthie Joan that The Triplets? What is the Secret of St. Gabriel's Tower? What exactly is St. Gabriel's Tower? All will be answered in the first of A Poplar Cove Mystery