The parents were taking their child to the fair. This is evident from the opening lines of the story where the child narrates his excitement about going to the fair with his parents. However, the child gets separated from his parents while he is engrossed in watching the various attractions at the fair.

Details of the incident:

- At the fair: The child and his parents were at a fair. The child was fascinated by the toys and other attractions at the fair.

- The child gets separated: While the child was playing with a toy, his parents moved ahead. When the child looked up, he couldn't see his parents anywhere. He started calling out to them but there was no response.

- The child's efforts to find his parents: The child started running in different directions, hoping to find his parents. He asked the people at the fair if they had seen his parents, but nobody had seen them.

- The child's fear and anxiety: As time passed, the child started feeling scared and anxious. He started crying and calling out for his parents. He felt lost and alone.

- The strangers who helped the child: Some kind strangers at the fair noticed the child crying and asked him what had happened. When they found out that he was lost, they offered to help him find his parents.

- Reuniting with the parents: The strangers helped the child search for his parents and finally they were reunited. The child was overjoyed and hugged his parents tightly.

In conclusion, the parents were taking their child to the fair when he got separated from them. The child's efforts to find his parents and the strangers who helped him make the story a heartwarming tale of love and kindness.