From Halopedia, the Halo wiki
In the original game, it is worth 20 Gamerscore and is unlocked by beating Sierra 117 from the start of the mission on Normal, Heroic, or Legendary. In the original game it is represented by a blue plate with the Roman numeral I on it.
Halo: The Master Chief Collection
In The Master Chief Collection it is only worth 10 Gamerscore, though it can also be unlocked on any difficulty. The achievement's Xbox art is the loadscreen image for the level.
- The name of this achievement could be a reference to the short film, "Halo: Landfall", released as marketing material for Halo 3. In Halo: Landfall, Marines are in search for Master Chief's location when he falls to Earth.