Answer:
At first, Tasha is forced to take care of her younger brother Junior during the summer.
She doesn't want to do it since she planned to spend the summer with her friends, and feels that her younger brother follows her everywhere.
Junior was committed to obeying Tasha in whatever she said, but Tasha kept treating him badly.
Tasha was disobeying all the precautions her mother had given her, such as inviting her friend home, leaving the neighborhood or losing sight of Junior. While Junior all the time reminded her that she shouldn't do that, which only irritated her more.
They went to a Playground, while Tasha was with her friends and wanted to have Junior away although he wanted to be by her side.
At one point she tells her brother "to get lost", and after a while she totally loses sight of him and finds him nowhere.
In the park there were abandoned dogs that were dangerous, but Tasha didn't believe that. Until she thought that one of these dogs had been caught his brother, and she even heard the barking.
Finally, it turns out that Junior just wanted to scare Tasha and play with her because she had promised to do it. The dog that was with Junior was harmless and his parents allowed him to stay with it.
Tasha finally realized that it was not so bad to spend the summer taking care of her little brother, and that he was not as terrible as he seemed.