One of Us Is a Traitor! is a Legion of Super-Heroes two-parter story published in Adventure Comics #346-347 (July-August, 1966), plotted by Jim Shooter and pencilled by Shooter and Curt Swan. Together with Supergirl story Brainiac's Blitz, it's Shooter's writing debut.
The Legion of Super-Heroes is short on manpower due to the absence of Brainiac 5 and departures of Bouncing Boy and Star Boy, so that they hold an audition and recruit four new members: Karate Kid (supreme martial artist), Princess Projectra (master of illusions), Ferro Lad (invulnerable and super-strong), and Nemesis Kid (can counter any enemy's power).
After the tryout is over, Superboy informs his teammates that the United Planets want them to investigate a new alien empire discovered at the edge of the known universe, ruled by the warlike race of planet Khundia. Their debriefing is suddenly interrupted by a message of Garlak, Warlord of the Khunds, delivering an ultimatum: unless the Earth surrenders within one hour, the Khunds will destroy the planet.
Alarmed, Superboy tells the Legionnaires about the Earth's newest defense system: three watchtowers which can wipe out any alien fleet. Nonetheless, Garlak let slip that his spies have infiltrated the United Planets, so that the towers might not be safe.
The Legion splits into three teams to protect each tower, but they ignore that one of their new recruits is a Khund spy.
Tropes:
- Accidental Public Confession: When Superboy declares he knows who betrayed the Legion and Earth, Nemesis Kid demands to know how they figured out he is a traitor. The team stares at him, and Phantom Girl answers they were suspecting Karate Kid, not him.Nemesis Kid: "All right! You've got me I surrender!"
Superboy: "Nemesis Kid! But..."
Nemesis Kid: "I admit it! I wrecked the towers! I destroyed the Legion weapons! I'm the spy! But how did you know? How did you find out?"
Phantom Girl: "We didn't! We thought it was Karate Kid! We were too prejudiced to notice you, too, were missing!"
Nemesis Kid: "Then...I incriminated myself needlessly! When Superboy said "Kid", I thought he meant Nemesis Kid, not Karate Kid!" - Alien Invasion: The Legion has to defend Earth from the Khunds, a warmongering race from another galaxy.
- Bullying a Dragon: In order to earn a post in the Legion, Karate Kid challenges Superboy to a fight. Superboy tries to talk him out of it (since Karate Kid is a normal human), but he will not be dissuaded. However, even though Karate Kid shows off impressive speed and reflexes, and is even able to toss Superboy over his shoulder, it is evident that he is only tiring himself whereas neither of his blows have damaged Superboy at all.
- Catch a Falling Star: Cosmic Boy performs two rescues of falling persons only in the first issue: he uses his magnetic powers to slow down a construction worker's fall, and catches his teammate Phantom Girl when she is falling from an exploding aircraft.
- Charles Atlas Superpower: Karate Kid technically has no powers, yet his mastery of martial arts is so great it allows him to fight superbeings.
- Defeating the Undefeatable: Two candidates to Legionnaire try to prove their worth by defeating someone undefeatable: Nemesis Kid challenges an atomic robo -which has only been defeated by less than a dozen of super-beings-, beating him by absorbing all his fuel; and Karate Kid challenges to Superboy to show off his fighting skills. Karate Kid loses, but the team are so impressed that a normal human managed to toss Superboy around for a bit that he is admitted.
- Deus Exit Machina: The story doesn't even bother to come up with a reason as to why Saturn Girl is not around during one global all-hands-on-deck emergency. It's clear the storyline would not have taken two pages, let alone two issues, if she had been present to read Nemesis Kid's mind.
- Do Not Adjust Your Set: The Legionnaires are reviewing footage a planet inhabited by the warmongering Khunds when all of sudden the face of Garlak, warlord of the Khunds, appears on the screen and demands the Earth's surrender within one hour, or his armada will destroy the planet.
- Energy Absorption: Nemesis Kid defeats an atomic robot by transforming himself into neutronium (an element which absorbs all energy) and drains the robot dry.
- Friend or Foe?: The commander of the Alaska Tower outpost is informed about an unidentified flying object approaching at missile speed, and believing it to be an attack, grants his gunner permission to fire. Then he realizes that their target is not a ship but a flying human, so probably a Legionnaire, but it is already too late to stop his men from shooting at it. Good thing it turned out to be Superboy.
- Friendly Fireproof: The commander of the Alaska Tower has his gunners to shoot at an incoming unidentified flying object, believing it be enemy aircraft before realize that it must be a Legionnaire. Fortunately it is Superboy, who cannot be damaged by any of their weapons.
- High-Speed Hijack: During the final battle between the Legion and the Khunds, Karate Kid spots the command aircraft flying over the city. Karate Kid leaps off his own flying vehicle, manages -barely- to cling to the cockpit -instead of crashing on the street several hundred metres below-, tear his way into the ship and knock Garlak down and out.
- Hoist by His Own Petard: Nemesis Kid infiltrates the Legion to sabotage the Earth's defensive systems prior to the Khund invasion. The Legion suspects that one of the newest Legionnaires is a traitor, but they are suspicious of Karate Kid, and the thought that Nemesis Kid is the traitor never crosses their minds until Superboy shouts "All right, Kid! The game's up!" and Nemesis Kid asks how they knew he was a spy.
- Human Hammer-Throw: Variant. Superboy grabs Karate Kid, and after spinning him around several times, since their fight was supposed to be a friendly duel, deposits the dizzy boy carefully in the ground.
- Kryptonite Is Everywhere: When the Khundian warlord Garlak gloats about his weaponry as delivering his ultimatum to Earth, he makes sure to mention his good supply of Kryptonite weapons.
- Lured into a Trap: Three Legionnaires are protecting the Alaska tower when they spot a spacecraft flying over the area, which is off-limits to all ships. Phantom Girl decides to go up and check the ship, in case that it is a genuine mistake; when she phases into the ship, though, she finds the vessel is empty, and her entry triggers an explosion. Fortunately, she is intangible, but she is still knocked off the sky by the shockwave.
- Master of Illusion: When the Legionnaires request Princess Projectra to demonstrate her power, they suddenly find themselves drowning under the ocean and beset by sea monsters, one second later are floating in deep space, and finally are back in their clubhouse. Projectra explains she has the power to project illusions, and the Legion agrees that her mirages are powerful enough to earn her a spot in the team.
- The Mole: The Khunds send Nemesis Kid undercover with the Legion of Super-Heroes to wreck Earth's anti-alien defenses.
- New Powers as the Plot Demands: Nemesis Kid has the ability to temporarily gain whatever power he needed to fight any single opponent, but his powers explicitly only work on one power at a time.
- No-Sell:
- Nemesis Kid can develop any power, including invulnerability, to counter any enemy attack.
- During his tryout, Ferro Lad shows his power off by transforming into living iron, asking the Legionnaires to shoot at him, and tanking all their energy attacks and weapons.
- The commander of the Alaskan outpost grants his men permission to shoot at an incoming unidentified flying object, before realizing that it must be a Legionnaire. Fortunately it is Superboy, who nonchalantly shruggs their attack off.Commander: "He's doomed! No one can survive so much combined energy! He'll be reduced to atoms!...Incredible! There's a figure flying from the smoke! It's Superboy![...]Are you all right? Those rays could have..."
Superboy: "I'm fine!"
- Not Enough to Bury: Subverted. The commander of the Alaskan Tower grants his men permission to shoot at an incoming unidentified flying object, before realizing that it must be a Legionnaire. Horrified, the man thinks their energy weapons have reduced an ally to atoms before realizing that it is Superboy, who has simply shrugged the attack off.
- Pietà Plagiarism: Lightning Lad carries his unconscious sister in his arms after Light Lass has been knocked out by a barrage of rays during one battle protecting the South American Tower.
- Red Herring: The story drops hints that Karate Kid is the traitor who is sabotaging the watchtowers that protect Earth from an alien invasion: he encourages Phantom Girl to check on a suspicious ship which turns out to be bobby-trapped, he has the kind of power and precision needed to rip the arsenal vaults' doors open, he goes mysteriously missing during one attack...Then Nemesis Kid confesses he was the saboteur, and the Legionnaires realize he was also missing during the whole mission.
- Rule of Three: Superboy builds three weaponized towers to protect Earth from alien invasions: one in Alaska, another in Sri Lanka and the third in Tierra del Fuego, and three teams of Legionnaires are sent to defend each tower.
- Screens Are Cameras: The Legion are watching footage of the Khund armada when suddenly the face of the Khundian warlord Garlak appears and smugly remarks he knows they are watching on their screens.
- Sixth Ranger Traitor: Nemesis Kid joins the Legion to spy on them for the evil Khund Empire.
- Stealth Hi/Bye: Cosmic Boy saves a construction worker from a deadly fall, and then sneaks away quietly before spectators can hound him for autographs.
- Story-Breaker Power: The only reason that Nemesis Kid was able to infiltrate the Legion and almost get away with his treacherous scheme, whereas Karate Kid was suspected of being a traitor, is that, for unexplained reasons, the team's telepath Saturn Girl is conspicuously absent during the entire ordeal.
- The Television Talks Back: When Garlak appears on the Legion screens to deliver his ultimatum to Earth, he addds "By the way, Superboy, we have Kryptonite weapons".
- There Was a Door: The Legion is discussing about the Khundian invasion when they are alerted that a raiding party is approaching the South American Tower. With no time to unfasten locks, the team bursts through the debriefing room's reinforced steel door.
- Thought They Knew Already: Nemesis Kid believes the Legion has pegged him as a traitor, so he surrenders and asks how they figured out he sabotaged the watchtowers protecing Earth from alien invasions. Then Phantom Girl tells they were blaming Karate Kid, not him.
- Villain: Exit, Stage Left: When he is surrounded, Nemesis Kid tries to develop one power to fight all Legionnaires. Since he cannot fight all of them, though, his own power teleports him out of there.
- Villain Teleportation: Nemesis Kid develops the power to teleport himself away when he is being cornered by the entire Legion.
- You Could Have Used Your Powers for Good!: After Nemesis Kid has been outed as a traitor and fled, Superboy comments sadly that he could have been the greatest Legionnaire annd helped people across the galaxy, rather than betraying his people for profit.Superboy: "He could have been one of the most powerful Legionnaires of all! Working with us, he could have done so much for the universe! But instead, he chose the path of treachery and disgrace!"