A vendor was selling helium balloons, and the boy wanted a blue one. It was sky blue, and it bounced on a string as the boy and his father walked along, admiring the people and the vendors.
After they paused to admire the paintings and sculptures of various artists, a sudden wind caught the balloon, and the boy lost his grip. The balloon was swept above the roof of a building, and it disappeared from sight.
The boy was distraught. His father offered to buy another balloon, but the boy was heartbroken. He only wanted the blue balloon. Teary eyed, he said he wanted to go home, so the father and son strolled through the park toward their house.
"Maybe," his father said, "the blue balloon will land at somebody else's house and find a home." This made the boy feel better, so they talked about where the blue balloon might travel before it landed.
"Maybe to the sea," the boy told the father, and he was happy again.
When his mother opened the door, the boy announced that "the blue balloon went free." The boy proceeded to tell her how he was sad about losing the balloon, but that the balloon needed to go free and find a new home.
"Sometimes, you have to go free before you find your home," the father said. Then, they told the mother about all the adventures they had imagined that the balloon might have.