Mr. Rivers is first seen waiting in line to sign the necessary adoption forms in order to adopt an imaginary friend for his son. Unfortunately, all of the forms had been stolen by Madame Foster and Bloo, meaning that there weren't any left. Eduardo, who was in charge of making sure the forms were signed, was instructed by Wilt to "make small talk" with the customer. Eduardo then begins listing off things that are small in size.
Later, Goo sent Mr. Rivers, along with the others waiting in line to sign their forms, into Mr. Herriman's office because she thought that he had taken them away in order to increase efficiency. Mr. Herriman sends everyone back outside and informed Goo that he had not, in fact, taken the forms and that they were put in place for organization's sake.
At this point Mr. Rivers and the rest of the customers have grown very impatient and are about to leave. Goo tries to get them to stay and eventually admits that the forms were in Old Man Rivers' house, at which point Mac and Bloo are able to get the forms back by blackmailing Old Man Rivers. At the end of the episode, Old Man Rivers introduces Young Man Rivers to his new imaginary friend that Mr. Rivers got for him, and Mr. Rivers thanks Old Man Rivers for watching his son for the day.