Thomas Avery (Martin Sheen) is an American ophthalmologist who goes to France following the death of his adult son, Daniel (Emilio Estevez), killed in the Pyrenees during a storm while walking the Camino de Santiago (the Way of St. James), a Catholic pilgrimage route to the Cathedral of Santiago de Compostela in Galicia, Spain. Tom's purpose is initially to retrieve his son's body. However, in a combination of grief and homage to his son, Tom decides to walk the ancient spiritual trail where his son died, taking Daniel's ashes with him.
While walking the Camino, Tom meets others from around the world, all looking for greater meaning in their lives. He reluctantly falls in with three other pilgrims in particular. Joost (Yorick van Wageningen) is an overweight man from Amsterdam who says he is walking the route to lose weight to get ready for his brother's wedding and so that his wife will desire him again. He is a warm extrovert who is the first to start walking with Tom. Sarah (Deborah Kara Unger) is a Canadian fleeing an abusive husband, who says she is walking the pilgrimage to quit smoking. Jack (James Nesbitt) is an Irish travel writer who when younger had desires to be a great author like Yeats or Joyce but never wrote the novel he dreamed of. He is the last to join the quartet and has been suffering from "writer's block." As the pilgrims travel the Camino, they occasionally meet and talk with other pilgrims — two Frenchmen, a young Italian and Father Frank, an elderly priest from New York. Thomas occasionally sees visions of Daniel alive and smiling among other people.
On the pilgrimage, the group experience challenges, such as when a young Romani steals Tom's backpack. Although the thief escapes, his father drags him back to Tom to return the pack, with embarrassed apologies, and an offer to attend a street party in compensation.
After the group arrives at Santiago de Compostela, Tom is accompanied by the other three members to Muxía. He scatters the remainder of Daniel's ashes at the sea there.
With Daniel's backpack on his back, Tom sets out on another journey.