It seems that U.S.S. Enterprise has gotten some new crew members, it does need to get replacements on a unfortunately consistent basis. It is Dudley Puppy, Kitty Katswell, and Keswick are on the ship. They have reached an unexplored planet, Captain Kirk is leading an away team for the planet survey. Science officers Katswell and Keswick know a little detail about going down to unknown worlds.

This a running gag about the guys in the redshirts, the beam down party consists of Capt. Kirk, Spock, Dr. McCoy, Scotty, Uhura, Sulu, Checkov, and Ensign Watson. Gee, I wonder who is going to die. Another Joke:
Kirk: Spock, how many ways to die on this planet?
Beep! Beep! Beep!
Spock: Six ways, sir.
Kirk: Okay the landing party will me, you, and six security officers. Lt. Washburn, you and others beam down wedown in just a minute.
Vavavaroom!
Kirk: Let's beam down. It should safe now.

The episode "The Apple" and "The Changeling" were some of the roughest on the guys in security department. Though the episode "And the Children Shall Lead" Kirk beams two security officers down to a planet that they are not orbiting. Those two officers were beamed into space. As someone points they don't check where beaming down to.

Dudley Donald Puppy is the titular protagonist of T.U.F.F.Puppy. Although he is still just a puppy, Dudley has the heart of a pack of full-grown dogs. He supposedly has no fear and hates wearing pants. Reared on his mother's strict morals, he was brought up strong, goodhearted, and destined to stop all badness and meanness in its tracks! Now if only he could figure it out how to follow that last rule.

The first clues to Dudley's past were shown in "Big Dog on Campus." During his high school years, he looked radically different. Being very skinny with no build, wearing very large braces and glasses, and covered in pimples. It was also revealed that he was a bullied outcast. Dudley's father is also absent and completely unmentioned, leaving fans to wonder where he is although it most likely will never be explained.

Although intelligent, friendly, and clever, Dudley is an incredibly air-headed and jumpy dog. As a T.U.F.F. agent, and a dog who loves the feeling of being good, he loves to catch bad guys like Bird Brain and The Chameleon. With his superior DNA, Dudley has tons of canine abilities that make him the ultimate mix of dog breeds and an awesome crime-fighting force. He has the best skills from every doggie gene pool (as well as being part billy goat somehow). With the stupendous speed of a greyhound, the superior sense of smell of a bloodhound, the astounding strength of an Alaskan malamute, and the powerful punch of a boxer, he cannot be stopped; however, Dudley is still a sloppy, excitable pup. Dudley clearly isn't a thoroughly trained dog, and still retains many regular dog-traits like chewing his butt and chasing tennis balls. In addition, he is prone to believing that dependent on others (usually, his mother or Kitty). Although he seems to like juice boxes, Dudley also seems to like grapes and anything grape flavored. If he isn't drinking a juice box, he is often seen drinking grape soda and also loves grape flavored snow cones, as seen in the episode Lie Like a Dog. In Mutts and Bolts, Dudley gained "super intelligence" from a lightning strike. This may mean that he will be smarter in the future, but it is most likely that this was only used for a gag.

Kitty Katswell is the deuteragonist of T.U.F.F. Puppy. She is T.U.F.F.'s #1 agent. Kitty is also an expert in combat, weapons, and detective work. She is Dudley's partner, assigned to train him as a T.U.F.F. agent, but often finds herself and her skills foiled by Dudley's antics.

Kitty is an agent at the Turbo Undercover Fighting Force, and is regarded as one if its greatest agents. Her claws are registered lethal weapons, and she is proficient at using many weapons, gadgets, and disguises. Despite this, she does have a few weaknesses, such as her shaky relationship with her mother and sister, her schoolgirl-like love for Eric the water delivery guy which can distract her

Kitty is known to have somewhat of a temper, but she is shown to be nice and kind and is most of the time shown as a tough-talking, no-nonsense girl. She is also said to be trained in the arts of combat, language and firearm use. As revealed in "Puppy Love," Kitty knows many things that guys like to do to impress girls.

Dudley often annoys Kitty with his stupidity and when he constantly chews his butt (also when he'd say the word "exactly," as revealed in "Diary of a Mad Cat"), but she still considers him to be a worthwhile partner and a good friend. Their partnership usually injures her in some comical manner. She gets very annoyed whenever her birthday is brought up, hinting an unmemorable childhood. Kitty shows her cat-instincts whenever she sees cat goodies and tends to purr and flirtatiously wag her tail when seen showing affection.

Despite being more mature, Kitty can also be as childish and silly as Dudley at times. This is shown in "Share-A-Liar," when she laughs at Dudley's practical jokes towards Snaptrap. Another example could be in Puppy Unplugged, in which Kitty rudely blows a raspberry at Dudley.

Keswick is one of the main characters of T.U.F.F. Puppy. He is best described as the T.U.F.F. (Turbo Undercover Fighting Force) scientist who creates gadgets for the agents working for T.U.F.F. Keswick is also T.U.F.F.'s very nervous resident genius.

The first clues to Keswick's past were said in "monkey Business." He implied that he came from another universe called Keswickia. However, this sort of contradicts the fact that he has parents, a sister, and a brother-in-law living in Petropolis. It could be said that they too came from that universe and followed him to Earth. This also shows that Keswick could be his own species of extraterrestrial animal form figuring he goes through animal stages throughout his life. In a sense, this means he is an alien. In Pup Daddy, this is also supported by the fact that he goes through different metamorphoses with age. He also refers to his species by what his name is, a keswick. His parents weren't shown going through a metamorphosis, but it's unknown whether the metamorphosis with age is even treated as canon.

Keswick is a very smart scientist who has made some major contributions to T.U.F.F. with some of his inventions. However, many of his inventions have also caused some harm to the team in the past as well, such as Rita, (some even spit out acid!). The Wrong Stuff showed that Keswick knows the art of Ninjutsu. He has a tendency to create his inventions very quickly like in Toast Of T.U.F.F. Keswick tends to behave like a dog in some episodes. For example, in Mind Trap, Super Duper Crime Busters and Organized Crime, he had his tongue out like a dog, and in one episode, he was even panting like one, lovestruck by Tammy. He also seems to have a passion for certain foods as he gobbles them down like a starving coyote such as in Dog House. In Mind Trap, he revealed that he was going through the dumpster for day old scampion. Dudley burped up a bag of Keswick's fishsticks that had a sign saying: DON'T TOUCH! on it in Chilly Dog. He seems to have strained relations with his parents. Contrary to popular culture, he seems to get along well with his in-laws. He also seems to have a strange sense of humor after he makes some sort of joke that no one really seems to get. Keswick also cares about his friends in a valuable way. In "Snapnapped", he has created a machine that makes donuts out of thin air and redesigned D.O.O.M. HQ using only soup cans and a shark tank. He refused to work for D.O.O.M. no matter how badly the other agents treated him. This means he is a caring friend, and will always be no matter what.