One afternoon, Bart is walking his dog, Toby, in the park near his house. Toby sees a black cat under a big tree and runs after it. Bart is a little angry that Toby runs away. But he has to look for him. There are so many roads in the park that Bart doesn't know which way Toby takes. Bart walks and walks. two hours passes. It is getting dark, and he feels very tired and hungry.“ Mom might be worried(担心的) about me,” he thinks.“ But where is Toby now?" Suddenly, he hears a voice, "Hi, Bart, are you looking for Toby? He is at my house, playing with my cat, Mimi. " It is one of Bart's neighbors, Mrs. Wilson. “ Thank goodness!" says Bart,“ I will not walk Toby again."