Here is how Starlight's dream, Luna visits her, and Starlight explains her dream goes in Thomas and Twilight Sparkle join Overwatch.
(Blizzard, HIT, Hasbro)
(Thomas and Twilight Sparkle join Overwatch)
(we see Starlight enter a battlefield saddened by how the soldiers clearly feel)
(when one of the soldiers looks up, along with Starlight, after we hear a jet-like sound)
Soldier #1:(taps one of his comrades and prompts him to look up)
(the soldiers smile at what they see in the sky)
(cut to the sky, where we see a humanoid figure)
(a close up reveals it is Pharah)
Pharah:(voice) We are hope.
(fade out of the battle field)
(Starlight is now in an alley in London)
(she sees a robot with its arm completely severed while a human mechanic tries to help)
(she notices posters on the walls that say "Omnic Rights" and some graffiti that says NOT HUMAN next to it)
(Starlight then notices something as the camera zooms out Reinhardt, a knight in shining armor, standing in front, glancing at them. The two look in Reinhardt's direction and cower as a Molotov cocktail is thrown at them. Starlight tries to use her magic to stop it, but it doesn't stop. Reinhardt immediately activates his Barrier Field to protect them)
Reinhardt:(voice) Ve are honor.
(fade out of the alleyway)
(fade into a tundra in a light snow)
(A MEKA unit is fighting a Titan-scale mech. The camera follows the MEKA; it turns and closes up to reveal to Starlight the pilot is D.Va)
D.Va:(voice) We are courage.
(fade out of the tundra)
(fades in to show Starlight a shot of Dorado's bank)
(she prepares for battle when she sees 3 bank robbers are shooting at some obscured target on the left. The closest robber, who has a gold-crown, turns his head to the right. The camera suddenly pans right and up to reveal Soldier: 76 to Starlight using his Heavy Pulse Rifle's shoulder stock to hit that robber on the cheek. The gold tooth can be seen flying off)
Soldier: 76:(voice) We are justice.
(switch to a shot of rubble implied to be the aftermath of a building's destruction. Starlight sees a little girl lying on her chest in the midst of the rubble. She looks up as a yellow light shines through the debris, getting Starlight's attention as well)
(cut to in front of the child, Mercy can be seen flying to her, with the Caduceus Staff in her right hand, and her left hand extended forward. Starlight could see a destroyed city and skyscrapers in the background)
Mercy:(voice) We are compassion.
(Fade in and into Numbani city)
(Starlight sees a heavy armed helicopter is shooting homing rockets at a running figure. The figure flashes forward 2 times to avoid the rockets. The camera follows the figure, revealing it to be Tracer to Starlight, and closes up in the middle of her front lip. She pulls out her Pulse Pistols)
Tracer:(voice) We are determination.
(Fade in and out to a close-up of Genji's face)
(he sheathes his blade as he sits upon a robot that is chopped up in a storm of blowing petals in front of a city)
Genji:(voice) We are harmony.
(fade in and out of the hilltop and into a city under attack)
(Starlight becomes angered when she sees some of the terrorists holding civilians hostage. Immediately, a man wearing a red and yellow costume with a black ops mask attacks, drawing many guards to him. A sniper shoots them all, and they fall into a smiley face position. The sniper ziplines down and cuts the ties on the hostages.)
Captain Sharpshot:(voice) We are freedom.
Lieutenant Lightning Burn:(voice) We are liberty.
(fade in and out of the city and into King's Row under attack from Null Sector)
(Starlight sees the Null Sector attacking innocent humans and Omnics. Some police are about to combat them when an ice wall comes up. Both police, Null Sector, and Starlight look up and see a woman wearing armor and a battle mask helmet, holding an ice spear. She leaps down at the Null Sector, coldness in her eyes.)
Death Winter:(voice) We are equality.
(fade in and out to show a closeup of Winston watching a rocket as it goes into space. A closeup of his face shows he is smiling)
Winston (Overwatch): We are Overwatch.
(the camera zooms out to reveal all the heroes and villains in the future standing on a platform in Watchpoint: Gibraltar behind Winston. Hanzo, Pharah, Tracer, Winston, Soldier: 76, Genji, Widowmaker, Captain Sharshopt, and Lieutenant Lightning Burn on the front line. Reaper, Death, D.Va, Mercy, and Reinhardt stand behind. Torbjorn, Lucio, and Zarya are standing on a higher platform on the left. Symmetra, Bastion, Mei, Junkrat, Roadhog, Zenyatta, McCree, Death Winter, Deathshot, Kulamorrow, Darkat, and Orisa are standing on the higher platform behind. A triumphant music plays)
(Starlight suddenly finds herself in her village at nighttime)
Princess Luna: I find this dream an interesting one.
(Luna appears out of the moon)
Princess Luna: Because I don't even know how it happened.
Starlight Glimmer:(bows to her) Princess Luna, I didn't know you would be here.
(the next day)
(we see Starlight explaining her dream to the team)