https://www.pcgamer.com/assassins-creed-odyssey-season-pass-includes-multi-episode-arcs-and-assassins-creed-3/

Ubisoft has revealed its post-launch plans for the upcoming ahistorical assassination game Assassin's Creed Odyssey, which will include a season pass featuring two multi-episode storylines and separate story missions called The Lost Tales of Greece that will be free for everyone. 

The first story arc, set to go live in December, will be a three-episode adventure called Legacy of the First Blade. It will introduce the first character to wield "the iconic hidden blade" (that'd be the wrist dagger) and reveal more about the history of the Assassins. The second arc, The Fate of Atlantis, is slated for the spring of 2019, and will set players off on a journey to the fabled city of Atlantis, where they'll square off against supernatural creatures and uncover its sunken secrets. (Remember that despite the series' historical trappings, Odyssey is not "shackled to history.")