It opens with a black screen. 4 white vines with thorns, 2 horizontal and 2 vertical, soon appear and seem to constrict the screen. They form the signature smash logo before crushing the screen and fading to white.
It fades into the N64 version of Hyrule Castle. A Maxim Tomato appears in mid-air and is instantly grabbed by Donkey Kong, who is hit by a blaster shot from Wolf which sends him reeling and the Tomato into the air before being grabbed by Wolf, who is knocked away by Little Mac who grabs the Tomato. He's hit in slow-motion by a Gordo and drops the Tomato, which rolls to King Dedede's foot and is picked up by the avian who goes to eat it but is hit in the face by a golden hammer that bursts through the wall. A large, golden figure steps out and slams the hammer into the ground before a smaller knight also dressed in gold steps out, twirling his spear.
It cuts to gameplay footage of Ornstein and Smough, showing them as a partner character who can swap between who's in the lead. Ornstein is quick and high-damage but very floaty and easy to knock about with few defense options. Smough is slower and has more lag on his attacks but deals way more knockout and can better tank hits. The two utilize their spear and hammer moves, as well as their ability to swap mid-combo to decimate Mario, Little Mac and Wolf. It cuts to King Dedede knocking Smough off the stage, killing him. Ornstein seems to absorb his essence from off stage and grows in size, the name on his HUD changing from Ornstein and Smough to Old Dragonslayer. Old Dragonslayer utilizes several new spear moves, as well as buffed versions of his original ones to make up for the lost partner. It cuts back to the cinematic with Ornstein and Smough approaching the 3 Smashers, who all get ready to fight. Suddenly, Ornstein is shot in the head which dazes him for a moment. He pulls a 9mm bullet out from his hemet and crushes it in his hand before the camera turns and zooms in to show the assailant.
The masked heister puts a duffel bag over her shoulders and pulls out the China Puff Grenade Launcher.
It cuts to more gameplay footage, showing Joy's gun-based specials as well as her ability to put down medkits and store items in duffel bags. She knocks Little Mac off stage with a drill, spikes Dedede with a well-aimed shot from the China Puff and jumps off-stage to execute Jigglypuff with a brass knuckle punch.
She and her fellow newcomers then fight. With her jumping around the larger Smough and riddling him with bullets and keeping her distance from the quicker Ornstein.
It cuts back to the cinematic with the fight breaking out into a free-for-all. Joy rolls and finds herself back-to-back with Wolf, with the two firing pistol shots at Ornstein and Smough and Donkey Kong respectively. Dark red ink rains on the two, much to their confusion. They both look up to see an Octoling hanging from the side of the castle.
She smirks and drops down with Octobrush in hand. Another transition to gameplay shows off Octoling, who's a semi-clone of Inkling who uses similar weapons to her, but with less damage and more knockback. She shows off the Octobrush, a faster version of the Roller, and Seekers which do less damage than Splat Bombs but lock onto targets. As Octoling joins the fray Joy and Wolf scatter, their temporary alliance broken. The camera pulls out from the chaos to show a futuristic helmet being held at someones side. It cuts to black and the sound of a M6D Magnum being cocked echoes into nothing.