At Rerun's request, Snoopy asks his brother Spike to leave his home in the desert near Needles, California and come to visit. When Spike arrives, Lucy is appalled at his skinny figure and takes him in to fatten him up. After a short stay, Spike gains significant weight, which he then loses from fear while riding with Rerun on his mother's bike. Because Rerun's mother still will not allow Rerun to have his own dog, Charlie Brown tries to find another home for Spike but to no avail, prompting Spike to return to his desert home.