This is how Opening and Thunderwing plots revenge goes in Thunderwing's Revenge.
[The film starts with recaps of the events of Thunderwing Returns]
Optimus Prime: (voice) Prievously on Thunderwing Returns.
Thunderwing: [in Twilight's mind] I must reclaim my body which means taking complete and total control of yours.
Thomas: We need to stop Thunderwing and fast.
Optimus Prime: Okay, Thomas.
Starlight Glimmer: Twilight!
Ratchet: That's not Twilight.
Princess Luna: That's Thunderwing.
Twilight Sparkle: [with Thunderwing's voice] Twilight can't hear you anymore.
Starlight Glimmer: You get out of my teacher's body!
[Twilight shoves the Dark Energon shard into Thunderwing's chest. Starlight and Trixie watch in horror as the shard disappears into Thunderwing's chest, reviving him. Thunderwing's red eyes snap open]
Thunderwing: Unicron, your most faithful servant has returned!
[end of recap]
[Ratchet, Princess Luna, Twilight, Starlight, and Trixie watch in shock as Thunderwing gets up and looks at them]
Thunderwing: Well, isn't that a surprise?
Ratchet: You won't prevail.
Princess Luna: We won't allow it.
Twilight Sparkle: You can't control my mind anymore.
Starlight Glimmer: What she said.
Thunderwing: I don't need to control your mind anymore. I now intend to steal all the magic out of every Pegasus, Unicorn, Earth Pony, and Alicorn. And thanks to me occupying your mind, I know where all those different ponies live.
Princess Luna: No!
Twilight Sparkle: We won't let it happen.
Starlight Glimmer: I'm with you, Twilight.
Thunderwing: Oh I will and it's all thanks to you Princess Twilight Sparkle. [unfurls his wings and flies away]