Both forty-something, Mari Anderson and Fritz Damler said no to a safe and scripted midlife and yes to saltwater, sand and the longest consecutive string of bad hair days ever recorded. With the ink barely dry on their marriage certificate, they rescued an old boat, loaded it with building supplies and pointed the bow toward a remote Bahamian island. What could easily have been a blueprint for disaster is instead a story of discovery, resilience and renewal. Plunge is told from both points of view (think Venus and Mars in Paradise) and sparkles with humor even as unexpected, sometimes...