The next day after the turtles returned to Equestria, Leo was in the castle looking for Twilight, because he saw that she was acting kind of weird, as if she had lost someone (in this case her friends), Leo found Twilight, she was in the library looking at a picture frame of her and her friends when they were young, Twilight looked sad to look at the portrait (Leo was right, Twilight was mourning her friends)
 
Twilight:  
I was fine with my friends  
Who would come into they life now and end  
I was fine, cause I knew  
That they did really matter until you  
I was fine when they came  
And we had fun together as if we were the same  
Over they, who they’d choose  
After all those years, I never thought I’d lose
 
It’s over, isn’t it?  
Isn’t it?  
Isn’t it over?  
It’s over, isn’t it?  
Isn’t it?  
Isn’t it over?  
I won and they chose me and they loved me and they’s gone  
It’s over, isn’t it?  
why can’t I move on?
 
War and glory, reinvention  
emotion, freedom, her attention  
Out in daylight, my potential  
Bold, precise, experimental  
Who am I now in this world without they?  
Petty and dull with the nerve to doubt they  
What does it matter? It’s over now  
Now I’ve got to be there for they childrens now
 
It’s… over, isn’t it?  
Isn’t it?  
Isn’t it over?  
It’s over, isn’t it?  
Isn’t it?  
Isn’t it over?  
I won and they chose me and they loved me and they’s GONE!
 
(Crying) It’s…over, isn’t it?  
Why can’t I move on?
 
It’s over…isn’t it?  
(Sniff) Why can’t I move on?
 
After finishing this sad song, Twilight starts to cry, and Leo knew he couldn’t watch his best friend cry, so he went to Twilight to try to comfort her.
 
Leo: Twilight?
 
Twilight is shocked to see Leo coming, she already wipes her tears
 
Twilight: L-Leo!? I, I-I was just …
 
Leo: I know
 
Seeing how Leo said, Twilight knew she could no longer pretend to be all right, and soon his tears dripped again
 
Leo: Twilight, I’m so sorry for your friends
 
Twilight extends his head on Leo, and Leo extends his wing on Twilight and puts his hoof on her head
 
Twilight: (Crying) And they didn’t even get a chance to see you and your brothers again, and meet Mira and … (Sniff) and I wish they were still here to see you, but that’s for many years, they haven’t has a long life like you and your brothers and it’s not even immortal like me … I (Sniff) I wish I had gone with them if I wasn’t an immortal alicorn!
 
Leo: But Twilight, if you weren’t immortal, you wouldn’t even have a chance to see us again. And anyways, this is not over, your friends are not gone forever.
 
Twilight: (Sniff) What do you mean?
 
Leo: You know, when you lose someone you love, that someone you love never leaves you, either by your side or in your heart, they are always with you, you can’t see them, but you can feel them.
 
Twilight hear Leo’s words, and start thinking, she touches her heart, closes her eyes and then she begins to hear cheerful laughter (the laughter of her friends) Twilight soon feels happy. She looks back at Leo and hugs him in thanks.
 
Twilight: Glad you finally came back.
 
Leo: Me too, and besides, you haven’t completely lost your friends, you still have me, my brothers, Mira, Spike, Littlepip, all of them who still love you
 
Twilight: Yeah, I have
 
Twilight and Leo hug as they hug, they didn’t know, and couldn’t even see, but behind them were the spirits of their Twilight’s friends, watching them proudly.
 
Pinkie Pie: This is our Princess
 
And soon they disappear
 
Song from Steven Universe (It’s over, isn’t it)
 
From TMNT Mutant Apocalypse and MLP Remembrance
 
Remembrance: https://www.youtube.com/watch?v=HZDhMKk4tfg&t=194s