At T.U.F.F. Headquarters, Kitty is preparing to give Dudley some training in weapons. She brings him into the weapons room, where Dudley sees a toaster and believes it to be a weapon for fighting bad guys. Kitty tells him that it is a toaster for making bagels, and Dudley pulls out a boomerang-blade object which he thinks is for cutting bagels. Kitty takes it away and tells him not to touch that without first consulting the manual since it is a very dangerous weapon, but Dudley idiotically tosses it anyway. The boomerang device busts through the wall of T.U.F.F. Headquarters and destroys everything with lasers. It also slices several of Kitty's whiskers, causing her to lose her balance. Dudley then learns from a sticky note that the Chameleon has escaped from prison. Keswick explains that the The Chameleon is a dangerous foe that can take the shape of any object, and he is threatening to get revenge on Kitty for putting him in prison. After hearing about the Chameleon (and pronouncing his name incorrectly, as Cham-ah-lee-on), Dudley begins to suspect that anyone in T.U.F.F. headquarters could be the Chameleon and beats up Keswick and the Chief using Kitty as a blunt object. Kitty calls Dudley an idiot and they get in another squabble, but soon the Chief assigns Dudley to protect Kitty since she's now unable to balance herself. Meanwhile, the other T.U.F.F. agents were put out of commission by Dudley's misuse of the laser boomerang.
Dudley and Kitty slide down through a chute into the T.U.F.F. Mobile, and are about to leave, when the car suddenly transforms into the Chameleon. Dudley is freaked out by the Chameleon's weird eyes and accidentally runs him over with the real T.U.F.F. Mobile while escaping. They arrive at Kitty's apartment, where Dudley pledges to not allow the Chameleon to get the jump on them again. He begins to blow up some objects around Kitty's apartment, and then he opens the window, inadvertently allowing the Chameleon to get in. They ward off the Chameleon temporarily, but Kitty is fed up with Dudley's childish antics and kicks him out of the apartment. Dudley comes back and knocks on her door, eventually making "puppy dog eyes" when Kitty initially refuses to give him another chance. However, as soon as she lets Dudley in, he reveals himself to really be the Chameleon. The real Dudley is outside, sulking to himself about wrecking Kitty's apartment while the Chameleon hops by in the form of a pogo stick with Kitty tied to it. Kitty yells at Dudley to get his attention, and Dudley, upon turning, realizes that Kitty's being captured by the Chameleon and tries to chase after them with the T.U.F.F. Mobile. Unfortunately for Dudley, when he presses the button to open the car, it blasts off without him, as he didn't read the manual.
At the Chameleon's hideout, he traps Kitty inside a glass container with his Cat Atomic Bomb, a bomb set to go off nine times, one for each of her lives. Although his blast resistant goggles fail to cover either of his eyes, the Chameleon starts blasting away anyways, but is distracted by a ladybug on the wall. Meanwhile, Dudley is scouting for Kitty when he recognizes the smell of burnt cat from earlier. Dudley tunnels into the Chameleon's hideout just as the Chameleon reaches the ninth blast, and Kitty's ninth and final life. Dudley uses the boomerang device from earlier to lay a trap for the Chameleon, who gets his tongue caught in a bear trap when he tries to catch a bug with it. Dudley then rescues Kitty from the glass chamber and puts the Chameleon in there in her place. Dudley leans on the bomb detonator, causing it to go off and injure the Chameleon. Kitty claims to lose her balance and purposely falls on the bomb detonator again, causing the Chameleon to turn into a pile of smoldering goo. After Kitty thanks Dudley for saving her, Dudley remarks he would have been there sooner but he stopped to read the boomerang's manual. Kitty points out that he read the manual to the fax machine, so Dudley tells her to run. They escape from the Chameleon's hideout just as the boomerang blows it up behind them, and freeze in mid detention to smile at each other as the episode ends.