How much of who we are is destiny and how much is chance?

In 1934, the three Miss Allens – Ruby, Adeline and Clara – arrive in the seaside town of Remarkable Bay for their annual summer holiday. It's the last time they'll spend summer as a family. Adeline is engaged, Ruby is weighing up an offer, and Clara is just eighteen and about to start her life. But by summer's end, the lives they have known will change irrevocably and a mysterious secret will tear the family apart.

Eighty-two years later, Ruby's great-granddaughter Roma Harris moves to the now sleepy Remarkable Bay, retreating from tragedy. Roma's distant cousin Addy arrives too, fleeing a life with too much drama. It's only when the women discover an old guest book that they start asking questions about the mysterious third Miss Allen. Who was she? Why has she disappeared from the family's history?

If they solve this mystery from their past, could it change their futures?