Here is how Dusty, Tigatron and Airazor found and warned Yuna about Bowser and his Company in Princess Yuna of Skylands.
Meanwhile, Prince Dusty Crophopper came to see Tigatron and Airazor.
Dusty Crophopper: Yuna's gone.
Tigatron: Gone? It can't be!
Airazor: How is this possible?
Dusty Crophopper: Yuna was sad because she never had the chance to stop Bowser, Kaos or the villains.
Twilight Sparkle: This is all my fault. Yuna was right to try and help, And I misjudged her.
Princess Celestia: It my fault too, Twilight. It's like I've doubted you during Cadance and Shining Armor's wedding. (sheds a tear) And that you wanted to go after Tirek, But instead, I've choose Discord.
Princess Luna: We all doubted Yuna's heart, I just hope she's alright.
Dusty Crophopper: We're going to get her back.
Cheetor: You three go on, The gang and I will look after the rest of Yuna's friend.
Tigatron: (as he and Airazor goes into Beast Mode) Good luck, Little Cat.
Cheetor: Same to you, Big Cat.
Airazor: Let's go!
Dusty, Tigatron and Airazor took off.
Later, Dusty, Tigatron and Airazor found Yuna.
Airazor: Yuna, Wake up. Wake up, Yuna.
Princess Yuna: (woke up) Dusty, Tigatron, Airazor. What're you three doing here?
Dusty Crophopper: We came to warn you that Bowser, his family, Kaos, Dr. Eggman, Metal Sonic, Aku, The Grand Duke of Owls, Thaddeus E. Klang, Feathers McGraw and Drako are taking over Equestria and Skylands.
Tigatron: We need you to come back, Yuna.
Airazor: All of Equestria is at stake.
Princess Yuna: I can't, I'm not needed here anymore. You guys don't need my help.
Dusty Crophopper: Yes we do, Your parents, Snowdrop, Isamu, Your relatives and the rest of our friends needed you.
Princess Yuna: (determined) All right, I'll do what I can to set things right.