Mara finds a brass key in her grandmother's old coat. What does it open? She does not know.
On the last ferry, an old man holds the same key. His name is Aldo. "Your grandmother was my friend," he says. "We hid a box under the pier."
In the morning they find the box. Inside are two paper boats and a note: "We'll sail again." Aldo laughs and cries. Mara folds a new boat. They sail it together.