Three H.I.V.E. graduates, Mammoth, Jinx, and Gizmo, are sent by the mysterious Slade to attack the Titans. While presumably well-trained and able to control their powers, the Titans get completely overpowered by the bad guys! Will the Titans be able to defeat these three villains and ruin Slade's plan?
Starfires better-than-her-at-everything sister, Blackfire, visits Starfire as the latter is suffering a personal crisis; she quickly makes friends with the Titans, and slowly begins to pull them away from Starfire, making her feel like an outcast.
The Titans attempt to thwart the villain Cinderblock as he breaks into a prison to free a specific prisoner, but their lack of teamwork lets both get away. Cyborg and Robin start arguing over who is responsible, and Cyborg quits. Cinderblock turns over the prisoner to the mysterious ""Slade,"" who when awakened, becomes Plasmus. The remaining Titans go after Plasmus, but are overwhelmed until Cyborg shows up and helps them defeat Plasmus after capturing Cinderblock, leaving Robin to wonder who is the mastermind behind the plan.
Dark clouds blow in, bringing Thunder and Lightning, two stormy brothers looking for a good time. Unfortunately, their idea of fun is wrecking everything in sight. Meanwhile, after one of Beast Boy's practical jokes on Starfire misfires, Beast Boy learns his lesson after realizing that, just like the brothers, there are penalties when you don't think of others. He starts to get through to one of the brothers, Thunder, but the mysterious Slade disguised as a Chinese sorcerer shows up and tricks the brothers into unleashing a fire demon. Beast Boy gets through to Thunder, who gets through to his brother - the two team up to summon a thunderstorm and put out the demon while Slade escapes.
Cyborg is reminded he's not completely human, when his power cell dies during a wild junkyard battle with the Amazing Mumbo. The Titans fear Mumbo has taken their friend, and search the city for Cyborg. But Fixit, a cybernetic hermit who finds and repairs broken things, finds Cyborg.
Raven's creepy tantrum of crackling black energy leaves Dr. Light begging for mercy, and the Titans see a new side of Raven- her temper. But, when Cyborg and Beast Boy find a Mysterious Mirror in Raven's room, they're suddenly transported to a strange nightmare world that's somehow connected to Raven.
Starfire and Raven don't really "get each other." Star doesn't understand Raven's repression, and Raven can't deal with Starfire's emotional outbursts. But when The Puppet King imprisons Robin, Cyborg, and Beast Boy inside wooden puppets and takes control of the boys' bodies. The girls are going to have to understand each other -- if they want to survive.
When a mysterious amphibious villain called Trident makes off with a boatload of dangerous Toxic Waste, the Titans hop into the T-SUB and go on an undersea adventure to put a stop to Trident. This is Beast Boy's big chance to morph into all sorts of undersea animals and show the team what a big hero he really is. But unfortunately another big hero shows up to steal the spotlight: a good-looking water-breathing teenage do-gooder named Aqualad.
Slade sends a team of Robotic Commandos to steal a high-tech chip. Now Robin is more determined than ever to find out who Slade is -- and what he's planning. But while Robin is obsessively researching his arch-nemesis, a mysterious new bad guy called Red X tries to steal the same chip.
The Titans awake to find themselves captured as prisoners of Mad Mod, a madcap bad guy in a psychedelic suit. Mad Mod has decided to teach the teens a lesson, creating a massive mind-bending school full of optical illusions and brain-washing hypno-screens. Will the Titans be "re-educated" and lose their minds in the process?
Robin is haunted by dreams of becoming more like the mysterious Slade, while the Titans must track down the mastermind to stop his detonation of a chronoton bomb. Robin catches up to Slade while the others defuse the bomb, but Slade reveals the bomb was a lure - Robin's teammates now have microbombs secretly placed in their bodies, and Slade will detonate the bombs if Robin doesn't switch sides and becomes his assistant. Reluctantly, Robin agrees... (to be continued)
With no signs of Robin since Slade's "Chronoton Detonator" turned out to be a fake, the four remaining Teen Titans search the city for their missing leader. But their search is cut short when the Titan signal alerts them to a new villain in town.
Cyborg has just finished building the vehicle of his dreams: the super-cool , uberfast, ultra-high-tech T-CAR! Cy grins like a proud parent as he shows off his "baby" to the other Titans. But before Cyborg can take his cool car out for a spin, the Titians are called to an Electronics Superstore where an electrical menace called Overload is wrecking havoc. Our heroes race to the scene - and Cyborg leaves behind his beloved car parked out front with its high-tech alarm set. But when they emerge from the store with Overload in custody, Cyborg freaks: the T-Car is gone!! A wild adventure unfolds as the T-Car changes hands from bad guy to worse guy - Cyborg races all over town, trying to catch up. Can Cyborg get his "baby" back - or is the T-Car lost forever?