Zazu gets fired from his job after he forgets to count one single animal on his (nearly) complete list of animals. He sets out in a quest to find out which animal he forgot.
"Zazu's Off-by-One Day" begins by introducing Zazu, a hornbill.
At the start of the episode, Zazu comes home and sees a big mess in the house. Gopher, Zazu's assistant, tells the hornbill that he was reorganizing, but Zazu forces him to unreorganize because the inspector is going to visit the next day. Gopher shows Zazu that the schedule has not been changed and therefore, the inspector is coming the current day, which makes the two panic.
Zazu swiftly cleans up his house and hides the mess to another part of his tree. But he soon realizes that the place he hid the mess is where the inspector is. When Zazu opens the door, causing the mess to get back in, the hornbill finds the inspector in his trash can.
The inspector tells Zazu that he's not concerned about the mess, he's concerned about his list of animals being incomplete, stating that there is one animal he forgot to include. He therefore fires Zazu from his job and has Gopher take the hornbill's place. After getting thrown out of his tree, Zazu goes on a quest to find which animal he forgot to count.
After recounting the animal population, Zazu falls asleep and has a nightmarish vision that he is surrounded by 1's. After Zazu wakes up, he runs into Rafiki. When he asks Rafiki if he knows which animal he forgot to count, the baboon shows him his reflection, making him realize that he forgot to include himself on the list. Zazu therefore flies back to his tree to get his job back.
While Zazu is on the way to his home, he finds some animals being incorrectly placed: elephants on trees, giraffes in holes, and fish in the sky. He sees that Gopher is responsible for the problem. While the inspector scolds Gopher for his job, Zazu returns and shows the inspector his now-complete list of animals. The inspector then begs Zazu to return to his job, stating that he never should have fired him in the first place and the hornbill agrees.
However, it is shown that Zazu and Gophers jobs are switched (although they are back to their original positions by the episode "Zazu's Off Day Off").
Scar makes a cameo when Zazu cleans out his trash can.
This is the fourth appearance of Simba in the series (not counting his appearances in pictures in "Palm Beached" and "Gabon with the Wind"), the fifth appearance of Rafiki, and the second appearance of Zazu.
The scene between Zazu and Rafiki is similar to the scene where Simba meets Rafiki, who reminds him that he's the king.