HBO has unveiled the second trailer for Game of Thrones, returning Sunday, March 31 at 9 PM ET with the Season 3 Premiere. Season 3 is based on George R.R. Martin's book "A Song of Swords," with new characters such as Mance Rayder (Ciarán Hinds) and Lady Olenna Tyrell (Diana Rigg) joining the cast. While we don't get any new footage from the series, this intriguing video features a three-eyed raven flying through a modern city, connecting our world and the land of Westeros.