Disclamier: I don't own Avatar The Last Airbender and Avengers: Earth's Mightiest Heroes.
This is the story before the Season 6 of Winx Club.
Chapter 9 Invasion Of Crescent Island
"We need to stop this before more Sleepers or the Kraang will come."Said Sokka
"How?"Asked Toph
"I... don't know!"Said Sokka
"Just need a plan kid."Said Iron Man
"Yes! A plan!"Said Sokka
"So... what do we do?"Asked Stella
"Easy. Got to Crescent Island and take both HYDRA and Kraang down."Said Mikey
"Talk always easier than do."Said Katara
"We know that."Said Wasp
"We need to invade that island now!"Said Captain America
"While you are plan for invasion. I'll prepare the ships."Said Zuko
2 hours later at Royal Plaza...
"We're ready now."Said Leo
"Umm... girls."Said Musa
"Riven called me. He's said that Tritannus and the Trix had invaded to the ocean of my homeworld."Said Musa
"Look like we can't go with you guys now."Said Stella
"Sorry guys."Said Flora and Bloom open a portal to go to Planet Melody.
"Winx to Melody!"Said Bloom and she's fly through the portal to Melody with her friends.
"Look like your help are only us and the Avengers."Said Donnie
"Let's go!"Said Zuko and the Fire Nation Battle Ships are going to the Crescent Island.
At Crescent Island...
"The army of the empire that known as Fire Nation is go at the place that known as Crescent Island that ruled by Kraang."Said Kraang
"If they think they can defeat us. They're wrong!"Said Red Skull
Around the Crescent Island, the HYDRA-Bots are rise up from the sea and go to fight the army of Fire Nation.
"FIERE!"Said Zuko and every Battle Ships start to shoot fire to the HYDRA-Bots.
"SLEEPERS!"Shouted Aang and he's point to the seven Sleepers that rise up from the sea.
"I'll take it!"Said Sokka and he's wear iron Boy suit and fly out with Iron Man, Ms. Marvel and Wasp to fight it.
The ships are land at the shore of the island and the army of Fire Nation are go down from the ships and fight with Kraang Droids and HYDRA Soldiers.
"Aang you come with me. We will take Skull down together!"Said Captain America
Leo use his katana cut two Kraang Droids. Raph throw Sai poke at head of Kraang Droid.
Mikey use his Nunchucks hit at heads of Kraang Droids. Donnie activate the blade of his Bo-Staff and poke it into heads of HYDRA Dreadnoughts.
Yellowjacket change his size to be giant and step on many of HYDRA Dreadnoughts. Hulk jump through heads of many of HYDRA-Bots.
Hawkeye shoot arrows to the chests of the Kraang Droids. Black Panther use his claws cut heads of the Kraang Droids.
The Sleepers are walk on the island and start to change themselves into Mega-Sleepers.
Then head of gigantic red skull fly out from the volcanic mountian and assemble with the Mega-Sleeper.
"This can't be good!"Said Leo
"How are we gonna beat it?"Asked Mikey
"I know how to defeat it. Aang your gliders. I need you to fly up there and go inside it's head
and take Red Skull down."Said Captain America and Aang activate his glider and fly to the head of Mega-Sleeper.
"SKULL!"Shouted Aang
"The Avatar? What a surprise!"Said Red Skull
"I will take you down!"Said Aang
"I think... not!"Said Red Skull and he's activate the magnet to pull Aang to hit at the wall.
"OUCH!"Said Aang
"Now... did Captain America told you that once I had enslave his partner Bucky.
Now you will be like him! AHAHAHAHAHAHAAA!"Laughed Red Skull
"NOOOOO!"Shouted Aang and he's pull his arm out and punch the Air Punch to him hit at the chair.
"OUCH! You dirty kid!"Said Red Skull and and Aang kick the Air Kick to him and he's float through the wall and Iron Man fly to grab him.
And now the Sleepers are overthrow into the sea but Aang fly out from it's head before it's will fall and explode.
"BOOM!"
"YEAH!"Said Everyone
"We did it!"Said Sokka
"You save the Fire Nation!"Said Katara
"And our lifes!"Said Toph
"BOOYAKASHA!"Shouted Mikey
Later at Fire Nation Royal Palace...
"Thank you for save us... Avengers."Said Aang
"And you too Turtles."Said Sokka
"Thanks!"Said Leo
"Wait a minute!"Said Mikey
"What now Mikey?"Asked Donnie
"How are we going to get home?"Asked Mikey
"Don't worry."Said Raph and he's grab his T-Phone and call the Winx.
"Bloom can you portal to send us back to Earth please?"Asked Raph and then Bloom come through the portal from Planet Melody.
"Are you finish with the invasion?"Asked Bloom
"Of course!"Said Wasp
"Good!"Said Bloom and she's create a portal and send them back To Earth.
"Bye."Said Bloom
"Bye."Said The Avengers and the Turtles and they take Red Skull and the HYDRA Soldiers and the Kraang that they found with them.
"Now time to go back to Melody. See you soon."Said Bloom and she's go back to Planet Melody.
"I gonna miss all of them."Said Aang
"Me nethier. Especially Iron Man."Said Sokka and he's wear Iron Boy suit and fly into the sky.
"WOO-HOO!"Shouted Sokka