Nine-year-old Marco is thrilled to go on a family picnic, not knowing that it will be the last one before his mother Anna leaves Italy to work abroad.

A year has passed since Anna left. Marco thinks about becoming a postman after receiving a letter from her on the day his older brother visits home.

Marco sets out on his first job to deliver an urgent letter for Gina. A fun day at the beach begins when he finally returns in the afternoon.

Marco wants to work to help his mother come home sooner, but his father won't listen.

Emilio helps Marco get a job washing bottles after school. Marco's father Pietro buys him a world map and the two bond for the first time in a while.

Marco has an ominous dream about his mother, and he worries when there is no new letter from her.

Poor Marco can barely see the ocean from his new place. He goes from roof to roof to find a better view and meets Fiorina the puppeteer along the way.

Marco's monkey delights onlookers by dancing in the puppet show. Peppino the puppet master invites Marco to dinner to show his gratitude.

When Marco shows Pietro's friend the way to the hospital, he is touched to discover his father testing a new treatment on himself to save a patient.

Concetta goes out on the streets despite having a cold. Her symptoms worsen, but the family can't afford a doctor. Marco goes to the clinic for help.

Fiorina must put on a show alone because everyone else is ill. Just as she gets safely through it with Marco's help, bad news arrives about Anna.

Marco once again considers going to Argentina. Emilio asks Renato to help Marco get to Argentina after having huge success with his ice cream sales.

Joy over the group trip to Argentina is cut short when Renato goes back on his word. Marco gives Amedeo a letter for Anna and entrusts him to Peppino.

When Marco reveals that he'd meant to be on the ship to Argentina, Pietro begins laying the groundwork to go himself.

Marco is discovered by Leonardo, but the ship's head cook is impressed by his persistence. Pietro learns the extent of his son's determination.

The head cook is touched by Marco's love for his mother and takes him under his wing.

Marco grows fond of his new life aboard the ship.

The ship arrives in Rio de Janeiro. Marco's friends help him look for another ship headed to Buenos Aires.

The ship Marco boards in Rio is full of sick people and the meals are dismal. Marco meets a lost little boy named Nino aboard the crowded ship.

Six days after leaving Rio, the ship sustains heavy damage due to violent weather.

Marco begs for the ship to go faster after waking from a terrifying nightmare.

The ship finally arrives in Buenos Aires. The person who knows Anna's whereabouts has run away, and Marco loses all his money to a pickpocket.

Marco is at his wit's after losing all his money. Then he hears about a woman named Anna who has been taken to the hospital, and rushes to see her.

After being left with absolutely no information on his mother's whereabouts, Marco hears a rumor about a familiar puppet show in the area.

Peppino and his family decide to accompany Marco to Bahía Blanca.