When the Waves Subside: There is Hope is written by a daughter for her parents out of appreciation for their strength, love, and perseverance since the disappearance of their youngest daughter, Heidi M. Allen. My parents started to look for glass rocks while they were dating and after my sister and I joined the family, the tradition continued. When the Waves Subside represents the similarities between broken glass and the parent grieving the loss of their child.