From Wikipedia:
A young boy, Bambino, goes on a midnight sailing trip with his father Papà and grandfather Nonno. After they anchor their boat in the middle of the sea, Papà presents Bambino with a cap similar to the ones he and Nonno wear. The two men disagree on how Bambino should wear it, with Papà pulling it low over his eyes and Nonno pushing it back on his head. Papà sets up a long ladder for Bambino to climb so he can set the boat's anchor on the full moon, and the three ascend to start their work of sweeping fallen stars off the lunar surface.