the following review is based on the japanese episodes that I (wampaq) saw, so the review isn't very complete. However as more episodes come out in English the review will be redone, to make it more complete.
Project SEEDS. Their goal is to protect Humankind as well as find a place for them to live. Inside one of the plants that allow the space ships to fly Vash and Knives are born. They are twin brothers and at first seem like nothing more than that. A woman named Rem Saverem is kind of like their Tutor. She teaches them all about being kind and how that can get you far. However a person on the crew of the ship specifically Brado beat up Vash for some reason I'm not sure of. Knives hates this and he is pushed more and more on. Eventually all but Rem, Vash and Knives are dead. Killed by Knives, or his powers. So they seek to evacuate the ship, but Rem realizes what Knives has done and stays behind to save all of the frozen people in the fleet. So Vash and Knives fall to the planet below and Vash discovers that all of this was Knives fault. On the way down Rem's ship is burned up in the atmosphere. Vash can't believe what has happened but Knives is happy. They see all of the other space ships falling towards the ground.