Michelle earns $221 selling lemonade on a very hot day in the fall, so she goes to the candy store with Kimmy. However, they get sidetracked while passing by a petting zoo. Michelle comes home with a donkey, whom she names Shorty. (Conveniently, he just happened to also cost $221 - after she tells the man selling him how much she has.) The problem is, he can't be taken back to the petting zoo because, according to Kimmy, it is kind of a "traveling petting zoo", and that "they were packing up to go to Seattle". So Danny agrees to let Michelle keep him until morning.
While everyone is asleep, or at least trying to get so, he starts braying. By this time, it is almost midnight. It seems that he is quiet whenever Jesse sings the Three's Company theme song, so he does so to him all night in order to keep him quiet.
In the morning, Stephanie discovers that he chewed a chunk out of a map she made for geography class the previous day. D.J. has an allergic reaction to him, where she is all sniffly and her eyes are all puffy. He then eats a hole through the painting of Danny's great-great grandfather, General Cornwall Tanner. The neighbors, who thought about shooting Shorty, reject Danny's idea of a free donkey. Everyone likes Becky's idea of donating him to the local children's zoo.