Avengers Assemble Against Doctor Doom

The Avengers: Doomsday trailer shows Thor calling the team together to fight against Doctor Doom.

Thor warns that their past efforts will be meaningless if they don't unite now.

The trailer ends with an exciting reunion between Thor and his old friend Steve Rogers, who is now Captain America.

Captain America looks different with a beard and regular clothes, and he easily lifts Thor's hammer, Mjolnir.

There's also a brief scene of Thor fighting Doctor Doom, who seems prepared for the attack.