As we know, Ness got kidnapped and was taken under Big Battlefield by the Villains and were on a large platform.

They savagely beat up Ness. Dark Pit used his Side Smash, Bowser Jr. used his Clown Cannon, which got Ness right in his gut. Wario used his Chomp, Ganon Flame Choked, Down Tilt, and Side Smashed him, King Dedede used Gordo Throw and Jet Hammer on him.

Ness: "Onch! Yow!"

Finally, Bowser growled and was running to Ness about to Dash Attack him. But everything faded black and something unexpected happens.

???: "PK Fire!"

Bowser was covered in flames, which wove out quickly. Ness then soon got off the ground, looking dizzy and saw none other the Boy of Nowhere, Lucas.

Ness: "Lucas!"

Lucas: "Hi, Ness. Time to repay a debt I owned you. Let me give you a hand!"

Lucas went to fight the villains.

Lucas: (Doing his Down Taunt) "Come on!"

Lucas did his Down Tilt and Stranded Attack on Bowser, a Side Tilt on Bowser Jr., Down Throw on King Dedede and then a Natural Aerial.

Lucas: "Ha!"

Lucas used his Standard Special, PK Freeze on Ganon.

His Side Special, PK Fire, twice on Dark Pit and Wario.

Lucas: "PK Fire!"

His Up Special, PK Thunder on Dark Pit, and then, Lucas connected PK Thunder to himself and hit the remaining villains.

Lucas: "PK Thunder!"

Bowser used his Fire Breath and Lucas was absorbing it by using his Down Special, PSI Magnet and gave Bowser damaged at the end of the attack. Lucas reflected Wario incoming on his Wario Bike with his Side Smash. Lucas meteor smashed King Dedede with his Back Air. Ness decided to him. Ness was punching a shielded Bowser Jr., but Lucas grabbed Mr. Saturn and broke his shield and Bowser Jr. became dizzy. Lucas Up Smashed him to the skies. The Villains started to retreat and Ness and Lucas were able to get back to Big Battlefield and reunited with the group, which never found out that Ness is gone.

Ness: "Guys, look who I bumped into!"

Everyone: "Lucas!"

Lucas: "Hi, everyone."

They were shocked.

Ness: "Guys, I have something very important to tell you'll. I had a vision and I saw a dark shadowy figure, that seemed mean and angry and wanted to destroyed everything in its path and we need to stop it. Also, somehow, it is expecting us to come to him. What do you think we should do?"

Mario then thought for a minute, but Spider-Man beat him to it.

Spider-Man: "We keep moving."

Ness: "Huh?"

Akame: "Spidey's right! If he wants us, he can have us. We're saving this world. And we will do it die trying, right everyone?"

Everyone: "Yeah."

Ness doesn't know what to say, but see's Lucas smiling thinking of the same thing and Ness agrees of their plan.

Ness: "Okay. I'm ready."

Everyone: "Let's do it, to it!"

They went to find anything suspicious and continued their adventure.

Mario, Donkey Kong, Link, Samus, Yoshi, Kirby, Fox, Pikachu, Luigi, Captain Falcon, Ness, Jigglypuff, Peach, Zelda, Sheik, Marth, Mr. Game & Watch, Dr. Mario, Falco, Meta Knight, Pit, Zero Suit Samus, Ike, Charizard, Diddy Kong, Lucas, Olimar, Alph, Lucario, R.O.B., Toon Link, Villager, Wii Fit Trainer, Rosalina & Luma, Little Mac, Greninja, Palutena, Robin, Lucina, Shulk, Duck Hunt Duo, Sonic, Twilight Sparkle, Rainbow Dash, Pinkie Pie, Rarity, Applejack, Fluttershy, Sunset Shimmer, Spider-Man, Mega Man, Pac-Man, Lloyd, Ichigo, Luffy, Naruto, Goku, Astro Boy, and Akame joined your team.