Cheyenne Mountain ( mission ) Cheyenne Mountain is the first part of the nineteenth and final mission in " " . Walkthrough . This mission includes two other areas , and is quite long . This area is the " outside " section . It is a good idea to have Rad - X for each squad member . You will also want a character with a decent Science skill for the next area . If you ' ve been using all of your Big Books of Science on one character that ' s plenty . For the final area , you will need a way to damage objects that you can ' t explicitly target . A Browning M2 or grenades work well . You can also pick up the Vindicator minigun and ammunition from enemies . This is a long mission , and you will really only find microfusion cells , . 50 cal , 2mm EC , and 7 . 62mm ammunition in quantity , so if you are using weapons that don ' t use these kinds of ammunition be sure to bring a healthy supply . For the Barnaky ending , you will need Simon Barnaky ' s locket or letter . The first objective more or less requires you to clear the path for the carrier . Enemies in this area are mostly humanoid robot s except where noted . The carrier is pretty flimsy , and if it is destroyed the mission is over , so it is best to be relatively thorough when clearing the area so that you don ' t get surprised while driving . You can leave the carrier at the bottom of the map until ready , you don ' t want to trigger it early . Objectives . Notable encounters along the path : Road along the west side of the map . The road then winds up the map . The last bend in the road ( the northeast corner of the map ) has some major defenses , including a behemoth and two turrets . Most of the turrets during the mission are powered by generators . There are three such generators . Destroying them powers down the turrents . The door itself is guarded by a humanoid robot and two hover robot s , all firing rockets . You can also snipe these from the top of the cliff relatively safely . Once you are sure the path is clear for the carrier , and before proceeding with driving the nuke carrier into position , move all but one member of your squad into the safe bunker , which has a few easy guards and some useless terminals . Take one character and use them to drive the nuke carrier into position . The character will have to get out of the carrier and run to the ladder near the farmhouse on the ledge , so make sure they aren ' t encumbered and you ' re familiar with the path to take . Have everyone use a Rad - X , drive the carrier into position , and run the driver to the ladder for the safe bunker . You have 60 seconds to make the run , so micromanage that character . It ' s possible that the back door to the bunker has to close to keep the squad safe . Once the nuke is detonated , you will automatically be moved to the next area . Alternatively , clear the path of robots and then bring the carrier into position . This saves you the trouble of having to protect the carrier . Notes . Northwest of the entrance to this mission , near where you find the nuke carrier , there are several invisible / deactivated NPC enemies . Players using turn - based mode will encounter these deactivated NPCs as soon as they encounter the two ( visible ) robot humanoid enemies at the first bend in the road . These deactivated NPCs cannot be targeted or hurt , but they will fire rockets , plasma , and mini - guns at your squad doing considerable damage as long as your squad is in range . The only way to avoid these NPCs is to play in CTB mode until you are well clear of the area they are in . This is the same game engine bug that affects the Osceolla mission after Gammorin is killed .