The Teen Titans respond to an emergency signal, sent from their headquarters. When the team assembles, however, they find that none of them is responsible for sending the signal. It's a trap, set by Doctor Light. The Teen Titans respond to the attack from Doctor Light. Kid Flash lunges at Doctor Light, passing through a light illusion, then slamming into the far wall. Doctor Light binds Robin in solid light manacles. Speedy floors Doctor Light, with a mirrored trick arrow. Doctor Light is quick to recover, taking out Wonder Girl.
An errant shaft from Speedy, injures Kid Flash, causing him to barrel into Speedy. Doctor Light blasts Mal Duncan, then flees, with Wonder Girl as his prisoner. Robin pursues, only to be taken captive, as well. Kid Flash's injured knee keeps him from joining the pursuit. Angry, and frustrated, at their defeat, the remaining Teen Titans opt to disband, and pursue Doctor Light separately. Doctor Light tortures Wonder Girl, to force Robin to reveal secret information about the Justice League of America's satellite headquarters.
Doctor Light has positioned an enormous magnifying glass in orbit. With it, he plans to incinerate the satellite, with both the assembled members of the Justice League of America, and the Teen Titans, onboard. To prevent the Teen Titans from warning the Justice League of America, Doctor Light goes after Kid Flash and Speedy. Doctor Light intercepts Kid Flash on the outskirts of Central City. Doctor Light takes out Kid Flash, mere seconds before he can reach his mentor, the Flash.
Doctor Light finds Speedy back at the Teen Titan's headquarters. Quickly defeating Speedy, Doctor Light teleports away, not even bothering to engage with Duncan. Doctor Light's casual dismissal of Duncan as a threat enrages Duncan. No longer content to rely on only his skills to fight crime, Duncan raids the Teen Titans' store room. Duncan outfits himself with a strength enhancing exo-skeleton. Duncan then adopts the mantle and costumed identity of the Golden Age hero, the Guardian.
Piloting one of the Teen Titans' shuttlecraft, the Guardian journeys to the Justice League of America's satellite headquarters. Doctor Light ambushes the Flash. Doctor Light teleports the Teen Titans on board the satellite. The Guardian confronts Doctor Light. Still dismissing Duncan as a threat, Doctor Light seriously underestimates him, as the Guardian. With Doctor Light momentarily stunned, the Guardian frees the Teen Titans. Kid Flash tends to the downed Flash, while the Teen Titans beat the living daylights out of Doctor Light. Having learned from their mistakes, the Teen Titans vow to move forward, as a team.