A glass bottle is fragile, but it is also seaworthy when sealed. It gets picked up by currents and pushed by winds, and though it’s impossible to predict where it will travel, people have long been fascinated by the movements of such bottles. Many people have attempted to learn more about the world by sending messages in bottles like this, but one bottle will change two people’s lives forever. It travels 738 miles in 26 days, landing near Chatham, Massachusetts.

Theresa Osborne walks along the beach in a cold December wind. She doesn’t feel anything, and no one knows where she is or what she plans to do. Opening an envelope, she withdraws three well-read letters, hoping she won’t need to reread them so often after today. She can see the spot where everything began, and her memory moves back in time. 

On that day, she went jogging at sunrise. It was a beautiful day on Cape Cod, and her 12-year-old son, Kevin, was visiting his father—Theresa’s ex-husband, David—in California. She was staying with her good friend, Deanna, the managing editor for the newspaper where she works, and Deanna’s husband, Brian.