The Smash Legacy is Super Smash Bros. Free-For-All's story mode, and a spiritual successor to The Subspace Emissary from Super Smash Bros. Brawl.
Stage 1: Battlefield
The game begins with a cutscene, similar to the one shown during the first trailer for the game. It shows the new Battlefield stage, until four beams of color, red, green, pink, and yellow, appear on the stage, chasing a Smash Ball. Finally, all four corner it, and dive in to break it, the beams shown to be Mario, Link, Kirby, and Pikachu respectively. The player then has a choice of playing as either Mario, Link, Kirby, or Pikachu, in a free-for-all battle.
After the battle, the winner will strike a pose before returning the others to normal, having being trophyized. They clap for the winner and are generally good sports, until all of a sudden, 8 more beams of color appear, challenging the 4. As everybody gets ready for the next fight, the player can now chose to play as Mario, DK, Link, Samus, Yoshi, Kirby, Fox, Pikachu, Luigi, Ness, Captain Falcon, or Jigglypuff in another free-for-all, but four of the fighters won't appear until four fighters already in the battle have been KO'd.
The victor of the second battle celebrates their win before returning the others back to normal. Everybody cheers, and get ready to head their seperate ways, until cannonball just barely misses Mario. Shocked, everybody quickly realizes where the attack came from, with one of Bowser's airships not too far away. It flies closer, with Bowser on the front deck, eager to meet his nemesis. As Bowser comes close enough, he snaps his fingers, and strange figures emerge from the greenery below. They start swarming the fighters, and must now fend off the horde. You can play as any of the characters from the last fight during this segment, where you must defeat 20 enemies.
As it seems all is well, and Bowser's airship begins to whir away, he sends out one last foe: a Goomba. Odd enough, until another figure from the strange attackers appears and shoots a weird, rainbowish aura at the Goomba, giving it a Final Smash like glow. It then grows, about 4 times it's size! The Mega Goomba must now be fought, and is the Boss of Stage 1. You can play as any character from before.
The Mega Goomba stumbles back before falling off the stage, shrinking before it dissappears into the foilage below. The group baffled, Mario decides to have everyone split, and see if they can find any of those weird enemies anywhere else. Everybody is split into four groups, and heads their seperate ways. Mario, Ness, and Kirby head North, Luigi, Yoshi, and DK head South, Fox, Samus, and Jigglypuff head East, and Link, Pikachu, and Captain Falcon head West. Not too far away, a figure is shown looking from a treetop, and grins as it's fists becoming covered in the rainbowy aura from before until the cutscene and stage ends.