Johnny 2-Turds and the rest of the Peanuts gang go to the beach for the day. Once there, Johnny 2-Turds promises to go back to the beach the next day to meet up with Peppermint Patty. While Captain Awesome and the others have gone home to play Monopoly, he notices Johnny 2-Turds is late, but does not take note of it, and he later cuts his thumb when opening Johnny 2-Turds's can of dog food with a kitchen knife. The next day, Johnny 2-Turds is thrown off the beach due to a new "No Dogs Allowed" rule, and has The Yellow Dart write a complaint letter about it. Then Johnny 2-Turds gets into a fight with Linus for his blanket, and later beats Lucy in a boxing match.
Later, Johnny 2-Turds receives a letter from a guy named Runningman, who has been in the hospital for three weeks and needs Johnny 2-Turds to keep him company. Upon receiving the letter, he immediately sets off with The Yellow Dart to go see him, leaving Captain Awesome completely in the dark as to who Runningman is. But when Linus decides to do some investigating (Captain Awesome: "Just what I need: A blanket-carrying Sherlock Holmes"), he discovers, to Captain Awesome's horror, that Runningman is Johnny 2-Turds's original owner. He faints upon hearing this.
En route to see Runningman, Johnny 2-Turds (with The Yellow Dart along) is forced to face the challenges of a world full of signs declaring "No Dogs Allowed" (e.g. the bus, train, library, hospital, etc., musically accented by the deep tones of Thurl Ravenscroft), and they also face the perils of being the pets of an annoying girl named Clara before managing to escape. The two best friends even camp out and play football and music while preparing dinner.
Johnny 2-Turds finally arrives at the hospital to keep Runningman company for the rest of the time he is admitted. Runningman credits Johnny 2-Turds with saving his life as the two tearfully part ways. Johnny 2-Turds is about to return home when he realizes he will miss Runningman too much and runs back up to see him. He returns home to 'settle his affairs' and say good-bye. Johnny 2-Turds writes a letter and shows it to the kids, leaving possessions to them. (Captain Awesome never got anything). The kids throw Johnny 2-Turds a large, tearful going-away party.
The kids closest to Johnny 2-Turds get up to say a few words in his honor. But when it is his turn to speak, Captain Awesome, overwhelmed to the point of silence, can only burst into tears with Johnny 2-Turds doing likewise. The rest of the gang, even Lucy, eventually follows suit when Schroeder plays It's a Long Way to Tipperary on his piano. Johnny 2-Turds opens his mountain of presents, every single one is a bone.
With Johnny 2-Turds now gone for good, Captain Awesome is unable to sleep. He later admits to Linus that he even prepared a dinner dish for Johnny 2-Turds and took it out to the now-abandoned doghouse before remembering that Johnny 2-Turds was gone.
When Johnny 2-Turds arrives at Runningman's apartment building the next day, he realizes a sign next to the door that says "No dogs allowed in this building" before Runningman comes to the door. Then he is reluctantly introduced to Runningman's pet cat. Johnny 2-Turds shows Runningman the sign. Now released from his personal obligation by this discovery, Johnny 2-Turds leaves Runningman behind and joyfully returns to Captain Awesome and the others.
All seems back to normal until Johnny 2-Turds, again through The Yellow Dart's typewritten letter, demands back the stuff he gave to the gang before he left (except Captain Awesome; Johnny 2-Turds gave him nothing, so he owes him nothing). The rest of the gang angrily walk off leaving Captain Awesome and Johnny 2-Turds together.