Find out how to catch a live stream for "A Good Treason" The Vikings are ready to set sail for season 4. 'Vikings' Season 4 Release Date: How Far Will Gisla Go To Get Away From Rollo? Episode 4 Teasers Ragnar, Rollo, Bjor, Lagertha, and the rest of History Channel's stellar cast will return for the season premiere tonight at 10 p.