On a stormy night, Donald and his nephews overhear the radio announcer, Breckenridge, notify the listeners that a gorilla named Ajax has escaped from the city zoo. The nephews huddle in fright, and Donald laughs at them. As a prank, Donald frightens his nephews with gorilla hands to make it seem as if he is Ajax. The nephews view Donald from the keyhole and in order to get revenge on their uncle, they dress up in a gorilla suit and lay under Donald on the armchair, and take a bite out of Donald's lollipop while Donald is not noticing. Donald hears the crunching noise and discovers the mark left by the costume's sharp teeth in the lollipop and stares up at the fake gorilla, pale in fright, he runs away. The nephews pop up from inside the suit and laugh hysterically. At the same time, the real Ajax appears in front of the window and breaks into the house. Ajax then lets out an enormous roar and the nephews run away, still wearing the suit. Donald, who was hiding in a vase beneath an umbrella, spots them and their disguised gorilla suit and angrily chases them. Ajax appears in front of them and the triplets escape, but Donald momentarily assumes that Ajax is the triplets in disguise and grabs Ajax by the face to remove the "disguise" before spotting them. When Donald realizes that Ajax is not the fake gorilla, Ajax roars at him and Donald almost faints until Breckenridge says that he can master any wild animal by looking them straight in the eye. Donald stares into Ajax's eye; however, he sees his pupil forming a tombstone reading "Here lies a dead duck". As Ajax is about to eat Donald alive, Donald shoves an umbrella into Ajax's mouth and escapes. Donald and his nephews are then shown quietly tiptoeing away to search for Ajax, but one of them accidentally spills some candle wax on Donald's behind and later burns Donald's back. Donald's head briefly turns into a boiling kettle, and he angrily drives the triplets away and gets his hand burnt on a doorknob due to unknowingly holding the candle's flame under it. Later, Donald searches for Ajax on his own, and unfortunately crosses paths with the gorilla, who was standing on his head, and Donald does not even realize his presence until his tail feathers hint him, and Ajax starts chasing Donald. Ajax chases Donald through his house, causing a lot of havoc of the house, like scraping a column, crashing through the ceiling to the bedroom after Donald tricks Ajax into running up a ladder at the end of the stairs, and destroying wooden planks from a really long table. Ajax pushes the table to try to crush Donald and then tries to bite Donald's tail, but it pokes him in the eye. Amid all these things, with the help of Breckenridge, the nephews use tear gas in an attempt to stop Ajax, and it successfully subdues Ajax, but affects Donald as well. Tearing up, Ajax and Donald console one another and crying as the cartoon ends.
