A Thousand Broken Pieces tells the story of Savannah Litchfield, a seventeen-year-old girl grappling with the loss of her sister, Poppy, who died three years ago. Savannah feels stuck in her grief, and the pain becomes more intense as she reaches the age when Poppy passed away. Encouraged by her therapist, Savannah reluctantly agrees to join a trip around the world aimed at helping teens cope with loss. She takes with her an unread journal that Poppy left behind, hoping to find some connection to her sister once again.

On the same journey is Cael Woods, a young man whose life has been consumed by the anger and sorrow of losing his older brother just a year ago. Once a talented hockey player, Cael can no longer step onto the ice without being overwhelmed by memories of his brother. His parents enroll him in the same trip for grieving teens, even though he has no desire to go. As Savannah and Cael travel together, they begin to heal and find comfort in each other. Their shared experience of loss allows them to discover a small light amidst their darkness. Through their connection, they learn that together, they can piece back their broken hearts and move toward a path of healing.