Save Perry from the Heartless

Black Doom: Why do you still care about that bunny? He has all but deserted you for the sword and his new friends after all.

Duck: I don't care about him. I wws just messing with him a little.

Black Doom: Well... I guess you're right. Beware the darkness in your heart. The Heartless prey upon it.

He left to the Portal

Duck: Mind you own Business!

Then our Heroes have arrived

Ace: Duck! What's wrong with you? What are you thinking? Do you now what you done?

Duck: I was going to say something to you, Ace. You seem interested in saving the World's and showing off that Sword these days. Do you ever want to save Lexi and the Others?

Ace: Of course I do.

Then they heard a noise, they saw Perry trapped inside a Parasite Cage

Duck: Ready for this?

Ace: Yeah. Let's do it!

They fighting Parasite Cage and it let go of Perry and Duck is going down to catch him even our Heroes is. And they are back to where they met Phineas and Ferb

Phineas: Perry! Perry! Please, give me back our Platypus.

They saw Duck holding Perry Unconscious

Duck: Sorry, kids. I have some unfinished business with this Animal.

Phineas: Don't call him that! Perry is a Platypus.

Duck: He is unusual, but not many animals who doesn't have a Special heart. I'm not sure, but maybe he can help someone who's lost their's.

Ace: Wait. Are you talking about Lexi?

Duck: What do you care about her?

He left and our Heroes are following him