Sierra 117/Walkthrough

Part 1:Walk It Off
A Brilliant walk through for this level (and a few others) can be found here http://nikon.bungie.org/gameplay/halo3_slaso/sierra117.html

It should be noted that there are Cavemen in this level; it is suggested you go and find them.

From the levels beginning, there really is only one way to go. It's a very linear space, and you shouldn't have any trouble following it. When the Phantom flies overhead, you should see a high rock on the right, just the right height to be jumped up to. Unfortunately, on Legendary you have a pretty useless weapon set, so just use the Pistol to open fire on the gold-armored Captain-Major Brute. As soon as the magazine is empty, get in motion. About five or six Grunts will show up from the left end of the log in pretty rapid succession. Head shot them and then finish off the Brute, if you need to. (Often, the Marines will have finished him by this point, or at least softened him up a little). Once that group is dead, dual-wield a plasma pistol with your magnum and move forward until you hear the sound of a Phantom inbound. Quickly, back up and take cover behind the log, or the Phantom will make you bleed for it. As soon as it departs, move forward again. The Phantom dropped what will be referred to henceforth as a lance, or a Brute leading about four or five Grunts. Kill the Brute first. At this range, he should be easy to "noob-combo," being that he's unaware of your presence. The Grunts will probably panic, but some may not, so drop the PP and keep the magnum ready. Once everything there is dead, drop the pistol in favor of a Brute Shot. There probably won't be much ammo in it, but that doesn't matter yet.( there is another way to go through this part. You'll need Plasma Grenades to accomplish this. After you've killed the Brute and took out the Grunts, go straight forward to the point where the Phantom drops the troops. As soon as the Phantom decends, throw a Plasma Grenade inside. It will work best if you could stick the gunner. Immediately after you've thrown the grenade seek a cover and stay put until the Phantom leaves. If done correct, you should've killed three to four Grunts and secured yourself a Plasma Cannon for later use throughout the level.) For the time being, just head left, through the foliage, and down onto a rock to claim the Blind Skull. Even if you've already gotten it, it can be an invaluable weapon here due to the massive melee damage. Once you've got it, get back up onto solid ground and head across the river towards the two Lances nearby. One is further forward, with Grunts on the sides and a Brute-Shot Brute on a rock. You can run in and make him hurt with the skull (my favorite) or attempt to noob-combo him. (The NC is always a safe, if cheap, bet, and you should use it when nothing else seems to work). The second lance is further away, with three Grunts and a Brute-Shot Brute who likes to hide behind trees. Watch out for him. Once they're all dead, drop the skull. Fill up on Brute Shot ammo and then progress on through the caves. Shortly, you will arrive at the second main encounter of the level.

This encounter and duel takes the form of a large, nonlinear valley, containing about fifteen Grunts (about half are asleep), five regular Jackals, three carbine Jackals, and five or six Brutes. This isn't an easy battle, but it shouldn't be impossible to manage. Some things to prepare: swap out the MA5C for a Carbine. Then, quickly move downhill and from tree to tree, killing sleeping Grunts. This will massively reduce the amount of incoming fire in the battle to come. Then, start by waiting for a small group of enemies to approach the clutch of plasma batteries on the far left side of the area, and carbine them for a multi-kill. So it begins.

The three snipers, being the longest-range foes, are your highest priority. One is quite close, on a rock one level down from the place where you entered the area—right below Thel 'Vadam. In fact, Thel 'Vadam may already have killed him. The two others are harder to find, hidden in the foliage on the ridge up at the top right side of the area. Pinpoint them by their shots, then zoom in and carbine-spam. (You have an infinite amount of carbine ammo in this area, so no need to hesitate). Once all three are dead, it's time to head down onto the valley floor. Fight your way across the river, taking care to look both ways for enemies as you cross. If you have picked up a Bubble Shield by now, I'd suggest that you deploy it on one of the raised areas just across the river to establish a beachhead. Target the Brutes first, then the Needler Grunts, then the Jackals, and then the regular Grunts. With the Brutes, you may want to use the Brute Shot melee to knock off their armor before you go for the head shot. By the time you've cleared the far bank of the river, you should have reduced the enemy forces to a single Lance. Swap out the Brute Shot for a Needler and use it to kill the Brute. Mop up the stragglers with Carbine fire. Once you've filled up on ammo again, move on down the path.

Up on the log above, Sergeant Reynolds is being menaced by a Brute. Needle the Brute, and then move forward under and past the log to get up the slope. There's a Carbine Jackal and a Grunt or two here, so be sure to kill them before moving on. Past this area is a section off to the left, out of which a few Grunts will come when you get near. Kill them and go into the place they came from. You can choose here to pick up the new, slightly better BR, or keep your carbine. I prefer the carbine, so I'll mention it in this walk through, but you can use the BR in its place if you please. At the far end of this area is a pair of Jackals (without Carbines, thankfully) and a rather sneaky Lance who I always get ambushed by. Again, use the Needler on the Brute and the Carbine on the Grunts. Follow the tunnel past the Cortana moment and you've completed this section.

Part 2: Charlie Foxtrot
To the left right after you exit the tunnel, is a dead Marine with a BR and some grenades. Take them as needed and then head down the path until you find yourself overlooking a large area by the river. On the right is a dead guy who had a whole mess of frag grenades: five, I think. Lob them one after another into the Covenant below. Once you've done so, jump down from the ledge and take a left to find another frag grenade cache to chuck at your foes. Although there are two Lances in the valley when you arrive, it's hard to say exactly how many will leave when the Phantom arrives. Usually, at least the Brutes walk away. But they're not your chief worry. Across the stream are two Jackal snipers, and these guys have actual beam rifles that are capable of a one hit. Use extreme caution and terminate at range. Once they're dead and the Phantom has left, you're free to begin the second and most difficult phase of this battle: attacking the dam.

This part can be obscenely difficult on Legendary, not simply because of numbers (though you will be vastly outnumbered) nor because of firepower (although you will be like wise out gunned) but because you tend to get nasty checkpoints. There are two ways to get up onto the dam: just jumping straight up from below (nearly suicidal but not impossible) or walking up the left path (slow but safer). If you want to jump right up, then go ahead and do it. I'd recommend moving a lot, throwing grenades a lot, dropping Bubble Shields a lot, and watching your back obsessively. If you choose the left path, then beware of the four Jackals (two normal and two wielding carbines) on the path itself, as well as the lurking carbine Jackal up on a ledge to the left.

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You should have picked up a Bubble shield somewhere along the line. Deploy it in this next area if under heavy fire. Once you're out of "sniper alley", you will come across Johnson's crashed Pelican, and a massive horde of Covenant Loyalist resistance. Pick up the Battle Rifle and Sniper Rifle at the crashed Pelican site before moving forward to the last section of Sierra-117. You do not need the Sniper Rifle here, but it is strongly suggested to grab it, as it will make taking out the Jackal Snipers and Brutes a lot easier.

Part 3: Quid Pro Quo
For this part of the mission you should have a sniper rifle and a battle rifle.

This happens fast so be ready as soon as the cut scene ends:

Look to the dam straight ahead of you, but step back a little. There are two Jackals with Beam Rifles across the way, and several armed with carbines scattered around. Zoom in with your sniper rifle and look at the right side near the building on the right end of the dam. There should be a Brute Captain Major standing there, Take him out with either one well placed sniper round or two. Next, remembering all of this happens quickly look at the left end of the dam (as far left as you can see, where the building on the left end of the dam starts). There should be a Brute Captain Ultra standing there. Take him out the same way as you did the major. Next, another Brute Captain Ultra will run past the one you just killed. Occasionally he will run past as you are killing the first, giving you the opportunity to get two for one (which is nice when you have no more than 24 rounds to work with). RELOAD NOW, even if you still have 3 round in the cartridge...... Finally, once the two Brute Captain Ultras are dead a Brute Chieftan (weapon class) will run out from the same area the second brute captain ultra ran out from.

He only has invincibility activated ~10% of the time and it is possible to take him out as he runs across the dam. He will sometimes stop if you hit him a few times, just shy of cover and end up easy pickings (try and kill him BEFORE he activates invincibility; it is good to have while being attacked). He is sprinting so you have to make your first shot a good one to stop him in his tracks or slow him significantly. Three to four sniper rounds are enough to take him down if you land all of them on his head/shoulders. It is critical to land a first good shot on his head or he will most likely escape you. If you do happen to miss him don't despair... Look at the building on the right end of the damn where he disappeared into. About 30% of the time he goes downstairs and emerges from the door at the base of the building on the right side of the dam. Here is your opportunity to finish him off, all without having to step out of cover. He may also move down to the building in front of you and just stand there. If he does, leave him until after the snipers are gone. After you take him out jump and take a quick scan of the area below you. Almost 100% of the time there will be another Brute Captain Ultra standing in the open. After you jump line your sight up on the ground in front of you so when you jump you barely have to aim at the brute below. One shot usually just knocks his helmet off, but jump again immediately and finish him off with a second shot to the head.

Now switch to your BR and plug the Sniper Jackal down in front of you. Switch back to your sniper, stay down, and wait until you can draw a bead on the rest of the snipers (there are about 5 of them).

You might not be able to kill the Chieftain with sniper fire, so be prepared for a long and drawn out close combat fight with him. However, it is possible to kill him by long distance sniping or BR fire (just wait until his invincibility runs out) It is also possible to stick the Chieftain, but only if you're very lucky. Plasma grenades do not adhere to a Chieftain, so the only way to stick him is to land it on the Hammer he wields. Lay down a pattern of Sniper fire until most of the Grunts, Jackals, and Brutes are gone, then jump on down, switch to your Battle Rifle, and move in. Your SR may be low on ammo, so exchange it for a Needler or Brute Shot or the grav hammer the chieftain was wielding. Note: After the cutscene, the Gravity Hammer wielding Chieftain is the most obvious high-value target, but the Jackal snipers in the area are a MUST to eliminate! You can always pick off the Chieftain later, but counter-sniping the Jackals should take priority because they are deadly accurate on Legendary.

About the Chieftain: if you see him charging at you and he's glowing white, that means he has his personal invincibility shield on and is preparing to make you a stat in the record book, so be prepared to run. Don't waste ammo or grenades on him when he has this shield activated, you won't do any damage. The best solution is to run around, or get to a high spot to avoid his Hammer and blast radius (Jumping helps, if timed right, although it is harder to do as he will often stop before striking). A good solution (when the shield is down) is to lob some grenades at him while he's charging and follow up with some automatic fire. The Brute shot is another weapon that is very effective, but never try to melee a Brute Chieftain! The Needler can also be particularly effective, but sometimes the needles bounce off his armor. Anyway, if you forgot to get the SR, use the BR to take out the Jackal Snipers, one by one. As for the other brutes, if you have enough ammo left in your BR, you can use it to shoot them in the head, or else work together with Vadam to kill them all, after killing the Chieftain. Beat down any Grunts that get in your way.

Upon rescuing Johnson from the makeshift prison the Brutes made, you will have one final engagement. Two Phantoms will arrive dropping a number of Brutes and Grunts. Engage them on the bridge and kill all of them to initiate Pelican Kilo 023 to fire upon the Phantoms destroying them easily. Hop aboard the Pelican by holding RB to complete the level and begin the cinematic.

Another strategy is to run around to the other side of the "Prison". There is a box you can hide behind and headshot grunts of the first wave.

To get the silver skull, where sergeant was held captive you should be able to jump on the roof of that and then jump onto the ledge of the large structure, or find another way, once on the ledge walk left to the bit where the mountain meets the building and in the corner should be the skull.