Legends of the Superheroes is a NBC live-action version of SuperFriends and was an umbrella title for two one-hour Hanna-Barbera TV specials based on the SuperFriends cartoon show that aired on NBC in January 1979.
Both specials preempted Project UFO, which aired on NBC from February 19, 1978 – July 19, 1979.
In the first episode, which aired on January 18, 1979, the superheroes must race against time to stop the diabolical supervillains’ plot to destroy the world. It opens in the cavernous lair of the superheroes arch-enemies. Meanwhile a few members of the Justice League of America gather together at the Hall of Heroes to celebrate elderly retired superhero Scarlet Cyclone's birthday. The party is interrupted by the Legion of Doom, who announce the spreading of deadly bombs in several places, and the heroes must follow clues to find them. It's all, actually, a trap to make the heroes drink Dr. Sivana's de-powering potion, which succeeds, but the heroes disarm the bombs and recover their powers. It is only after the whole battle is done that Scarlett Cyclone arrives to give his aid.
In the second episode the superheroes pay tribute to Batman and Robin in the form of a roast which even the villains attend. It is hosted by Ed McMahon. What's special about this roast is that it's a bunch of people in the hot seat, not just one guy. All of the heroes from the previous episode get their turn to be ripped on.
The specials were produced like standard variety shows of the time: on videotape, and with a laugh track.
This series reveals that Captain Marvel (and apparently all Fawcett characters) co-exist with the other heroes all on one earth. In the comics, the DC characters were part of Earth-One and the Fawcett characters were part of Earth-S. That is, until the Crisis on Infinite Earths, when all the earths were merged into one.
Warner Home Video's Warner Archive Collection released the specials on DVD on October 19, 2010.