If you are going to put together a team of superheros then you need a villain worthy of that threat. Say hello to Vandal Savage. Immortal and super strong, Savage is a big enough threat to warrant a team up but not so powerful that the heroes have no hope.
We've also been told that Caity Lotz is playing Sara Lance / White Canary post Lazarus Pit. So that explains how she comes back to life. That should be an interesting thing since Malcolm Merlyn is the head of the League of Assassins now and controls the Lazarus Pit. Was it his idea or Nyssa's? And how will her being back effect Oliver, Laurel and Thea?
And below is the video trailer the CW showed at today's upfronts.