Young Justice focuses on the lives of a group of teenage sidekicks attempting to establish themselves as proven superheroes as they deal with normal adolescent issues in their personal lives. The show corresponds to the present time of our world, a time period Vietti has called “a new age of heroes”.
The pilot episode (later re-broadcast as the opening two episodes of season 1) aired a month prior to the debut of the regular series and introduced four characters: Robin, Aqualad, Kid Flash, and Speedy. It established their desire for greater recognition and respect, namely, a promotion from sidekicks to full-fledged superheroes. Met with opposition from their respective mentors in the Justice League, Batman, Aquaman, Flash, and Green Arrow, the protégés react in different ways. Speedy resigns from being Green Arrow’s partner and begins calling himself Red Arrow. The others seek to persuade their mentors of their worth by secretly taking on a Justice League mission to investigate the Cadmus building. During their infiltration of Cadmus’ headquarters, the three heroes find a clone of Superman named Superboy. After the discovery, the team finds out Cadmus is creating living weapons called Genomorphs. The episode deals with this revelation, the origin of Superboy, and how this relates to a mysterious group of people called the Light. In the end, Robin, Aqualad, Kid Flash, and Superboy negotiate with Batman to organize a covert operations team as a practical contrast to the Justice League, whose celebrity status makes it difficult to maintain secrecy or initiate stealth operations. After consulting with his colleagues, Batman establishes Young Justice in a secret cave located inside a former Justice League headquarters, Mount Justice, a hollowed-out mountain. Here the teens are trained by Black Canary, given missions by Batman and are watched over by Red Tornado until episode twelve when this job is passed over to rotating Justice League members. Miss Martian makes an appearance at the end of the episode and joins as the fifth member.
The “Invasion” of the second season title refers to the potential invasion of Earth by the Light’s partners, the Reach, who are trying to control Jaime Reyes (Blue Beetle).