Destiny 2's Season of the Haunted is working through a compelling, character-driven story, one that dives into the personal traumas of some of the game's major characters as they try to deal with the new threat presented by Calus and the Derelict Leviathan. Like the best of Destiny 2's recent stories, it relies heavily on player knowledge from past seasons and expansions.

Generally, this is great, because with Bungie building on events of the recent past, Destiny 2 feels like a world that is changing as a result of the things that happen within it. But if you missed certain previous parts of the story, like the Forsaken or Shadowkeep expansions, this season might have you a little lost.

There's a lot of backstory you need to know to fully appreciate Season of the Haunted, stretching all the way back to vanilla Destiny 2, the Leviathan raid, and more. Here's a quick history lesson that will get you up to speed on everything you need to know about the Leviathan, Nightmares, Caiatl, Crow, and everything else this season--regardless of whether you've been around since the Destiny alpha, or just jumped in with The Witch Queen.