is taking its final descent on Netflix.The fourth and final season of the revived sci-fi action drama kicks off in just under two months, and during Saturday's virtual Tudum presentation, the official trailer for the first half of the series' last chapter — which will consist of 20 episodes — was released.The series, which stars Josh Dallas and Melissa Roxburgh, follows Montego Air Flight 828 after it lands after a turbulent but otherwise routine flight. While the 191 passengers and its crew believe only a few hours have passed, it's actually been over five years.