Season 1 of Citadel premiered on April 27, 2023.

One month after the events of the first season, Citadel spies are underground and being hunted by Manticore agents around the world. They're pulled out of hiding to join forces with a new team of unconventional spies when Manticore's Brazilian billionaire Paulo Braga threatens to unleash a cataclysmic piece of technology, built by Citadel's own Bernard Orlick, into the world.