Crow's Nest
From Halopedia, the Halo wiki
Holdout is believed to be the second campaign mission of Halo 3.
It takes place in a UNSC Base.
We know that like the first mission Master Chief is followed by the Arbiter
Upon completing it on the Normal, Heroic, or Legendary difficulties, the player will earn the "Holdout" achievement and 20 Gamerpoints.
References
Preceded by Sierra 117 |
Halo 3 Campaign Missions Mission 2 - Holdout |
Succeeded by The Road |