The title is a play on "unruly hair".
Elmer is a surveyor for a railroad company. He disturbs Bugs' rest by singing "I've Been Working on the Railroad" a little too loudly, "an unreasonable facsimile" of Frank Sinatra. Bugs proceeds to harass the hapless Elmer.
Elmer has Bugs at gunpoint, the barrel of the shotgun poking his chest. Bugs says, "Only a rat would shoot a guy... (turns around) ...in the back!" After some more taunting, Elmer fires at point blank range, obscuring Bugs in a cloud of gunsmoke. Elmer turns and says, "So I'm a big fat wat!" Bugs suddenly appears through the cloud, unharmed, and effects a Jerry Colonna-like schtick, "Aaah! Have some cheese, rrrat!" and stuffs a large wad of cheese into Elmer's mouth before scampering off.
Their antics set off trinitrotoluene in the supply store, and the explosion miraculously lays the ties and the track, followed immediately by an engine in full steam.
Bugs is riding away from Elmer at the back of the train, waving goodbye. He turns with a suddenly startled look, and leaps from the train, crashing and screeching to a halt. He stands up, brushes himself off, and says, "None of us civilians should be doing any unnecessary traveling these days!" He walks off down the tracks with a pole and a knapsack over his shoulder, into the moonlight, accompanied by an instrumental bar of "Kingdom Coming".
- Joe Besser - "Oh, you and your old gun, you craaazy!"
- Jerry Colonna - "Ahhh, have some cheese, rat!"
- On The WB, the part where Elmer has his rifle pointed at Bugs and Bugs tricks him into shooting him with, "Only a rat should shoot a guy in the back" was cut.
- Some local stations (and televised prints from the early 1960s) edit out the part where Elmer is looking through his telescope and Bugs puts a pin-up magazine in front of the telescope.
- This was the only Bugs Bunny short in which Frank Tashlin is credited, and one of two Bugs Bunny shorts directed by Frank Tashlin.
- This is the final Bugs Bunny cartoon to use the 1941-45 rendition of "Merrily We Roll Along". This is also the final Bugs Bunny cartoon not to have expanded credits, simply only crediting Supervision, Musical Direction, Story, and Voice Characterizations.
- This is the final cartoon in which Frank Tashlin receive onscreen credit; he is uncredited in his final four cartoons "Behind the Meat-Ball", "Tale of Two Mice", "Nasty Quacks" and "Hare Remover" due to them being released following his official departure from the Warner Bros. Cartoons studio.
- The engine on the train is a 4-4-0 (four leading wheels, four driving wheels, and no trailing wheels), commonly known as an American type steam locomotive, due to the great number of them produced in the United States.