"Know it All Ed" is the 1st episode of Season 2 and the 27th episode of Ed, Edd n Eddy. In this episode, the Eds discover a box of "Canadian Squirt Guns" and sell the squirt guns for 50 cents each to the kids. Eventually, everyone starts acting like they are in the Old West.
The Eds are playing around at the junkyard and generally having a good time when a chance tumble lands a box full of turkey basters in front of them. Edd recognizes these for what they are, but Ed and Eddy have different takes on the situation entirely, with Ed thinking that they're alien exploratory probes dropped off to conserve fuel during a mutiny of pulsating brain mutants and Eddy believing them to be Canadian squirt guns. Edd is doubtful, so Eddy fills one up and demonstrates its "proper" usage, and seeing this, Ed joins in. Delighted with this response, Eddy comes up with an idea: he and his friends will market the squirt guns to the kids of the cul-de-sac.
Thus the Eds find their way to the lane, where the kids are playing in a makeshift bowling alley. Eddy demonstrates the gun, showing off its power and accuracy, and all the kids are impressed. The advertising nearly done, all Eddy has to do is direct the kids to the sales counter at Double D's House of Import-Exports. When Eddy does this, the kids stampede the counter and pick up guns, along the way filling Eddy's money jar halfway full with quarters. Seeing this, Eddy realizes that today is his lucky day, and that they've got to keep the gravy train rolling.
To further this end, Eddy becomes "Marshall Eddy" and Edd "Double Deputy D". They then proceed to wander around the cul-de-sac, ticketing the cowpokes for the most minor offenses; Kevin gets a ticket for hitching his horse in a no-hitching zone, Rolf has to pay a fee for prospecting, Jimmy gets slapped with a railroad tax due to his retainer, and Sarah is fined for disturbing the peace when she yells at Eddy. Fed up, they declare that they won't pay their fines, and Eddy is at a loss for what to do when Jonny and Plank's runaway wagon bounds through the lane and crashes into a tree. Jonny topples out, tied up, and says that they were set upon by something evil that sprayed them with perfume. Eddy suggests that maybe the kids should have paid their fees, and the kids quickly cough up some cash to cover it. Eddy is happy until his jar is ripped from his hands by Lee. He reaches into his pockets and finds that his squirt guns have been stolen. The Kanker sisters have arrived, and they are the outlaws who plagued Jonny and Plank. When the defenseless Eds make a break for it, the Kankers lasso them and spray them with perfume before leaving, happy with their haul.
Eddy swears revenge, however, and soon the Eds set out to get it. Along the way, they pass three grave-like holes in the ground (later revealed to be mud pits for Rolf's pigs), which Edd takes as a sign that the community doesn't have much faith in them. Despite this, Eddy leads them onwards, and they make it to the construction site, where the Kankers are waiting for them.
What follows is an epic battle where the Eds do their best to defeat their nemeses. This includes novel techniques such as Ed firing five guns at once and Edd using a makeshift machine gun to fire at the Kankers. When the dust clears and the water stops flying, however, the Eds realize that they missed every shot, as the Kankers are still standing in front of them, dry and safe. The Eds are scared, as the Kankers ready their guns and fire. When the firing stops, however, Eddy realizes that the Kankers only hit their feet. Unfortunately, the guns were loaded with the Kankers' own brand of rubber cement. The Eds freak out when they see that they're trapped in the sticky substance, and the Kankers prepare for some "home cooking" with the Eds, with lipstick involved.
When the squirt gun stand falls apart, the writing on the 50¢ sign turns red for a moment.
The Kankers have purple perfume in the Eds' squirt guns, but when Lee says "And who's gonna help him?" they are shown to contain water.
Moments before the duel at the construction site, the Kankers are shown standing on asphalt. As the camera pans back and forth, the Kankers are standing on dirt.
During the duel, the Kankers were on flat land. At the end, they are standing on a mound surrounded with water.
Starting with this episode and throughout the rest of the series, Eddy's tongue color is green instead of yellow.
Eddy says "Twenty-five cents, or twenty-five days in the pokey!" Edd corrects this statement (and breaks the fourth wall) by saying, "Wrong cartoon, Eddy." The cartoon Edd was referring to is Hanna-Barbera's Quick Draw McGraw.
The naming scheme of "Krankshaft No. 5" is meant as a reference to Chanel No. 5.
When everyone pays Marshall Eddy their fines, Rolf puts half a button into the money jar.
The tie that Ed wears in this episode reappears in "Dear Ed", with Eddy wearing it.