Mass Effect 2: Horizon - walkthrough Mass Effect 2 guide, walkthrough

Last update: 02 June 2021

Received from: The Illusive Man [Normandy SR-2]

Description: You will be allowed to start this quest after completing four initial dossier missions, requiring you to locate potential crew members. You'll be automatically transported to the surface of planet [Horizon] after having a short conversation with the Illusive Man in the briefing room (Normandy's second deck). Start the mission by heading forward. You may ignore all the insects you see in the area, because they won't be interested in attacking you.

Expect to encounter the first group of aliens in a short while (first screenshot). You'll be going against several types of Collectors and the drones are going to be the easiest ones to kill. On the other hand, you will have to watch out for guardians and assassins, especially since they're going to be protected by additional barriers. I would recommend taking cover behind one of the pillars (second screenshot) to have a good view at the battlefield ant at the area to your left.

Make sure to pay attention to what your teammates are doing, because alien attacks can inflict massive injuries. It's important that an entire team is using objects from the environment for cover. Look around once it's safe, collecting power cells for your heavy weapons. Proceed to the next section of the colony. Be on a look out for a table with a data pad on it (second screenshot). A successful hacking attempt (mini-game) will reward you with 6000 credits.

The next large battle is going to take place after you've reached several buildings (first screenshot). Order your teammates to remain near the main passageway between buildings and you should move alone to your left. Aside from the Collectors you'll also have to watch out for husks. You may know them from the first game and they basically act like zombies, so it'll be important to prevent them from getting too close.

Make sure to eliminate all husks before dealing with the rest of the Collectors. A good vantage point is the left balcony (first screenshot), however you could also try taking enemy units by surprise after going through the right building. Once it's safe enter the nearest building (the one mentioned above) and find a datapad with 4200 credits.

You may move on to the next section of the map. Before you get there you should be able to encounter a dead Collector and it's recommended to scan its body to acquire a new plan for a research project. There's also a mutated body of a colonist nearby and examining it will give the main character a chance to comment the current situation.

Eventually you'll get to an entirely new building complex and you shouldn't be surprised to hear that it's going to be guarded by aliens. Start off by attacking an enemy stationed to your left. Your colleagues should go to the building to your right and take cover inside. I wouldn't recommend leaving them outside, because there aren't any good objects here they could use for cover.

Continue securing the surrounding area and watch out for a group of Collectors near the explosive containers (first screenshot). Naturally you should consider going for the explosions in order to kill them without taking any major risks. Once it's safe check the building where the rest of your team was stationed. There's a safe here (mini-game) with 4800 credits. You can also go to a second building located to the far left to collect a med kit.

Proceed towards the only unexplored building (first screenshot). There aren't any interesting items inside, so you'll just have to use a second door to head back outside. Examine a colonist in stasis when you get to the stairs (second screenshot). You can also use the stairs to check the room on the first floor. There's a computer there with 3000 credits.

Continue moving forward and MAKE SURE to examine an interactive object lying on the ground (first screenshot). This will allow you to take a new heavy weapon called a particle beam. Enter the building located to your left and order one of your teammates to take position near the closed door. As for the second member of your squad, he or she should stay somewhere behind. Alternatively you could also send your team to the room on the first floor you've a had chance to explore not long ago, but the preparations would take a lot of time. Open the door and make a few steps forward to watch an interesting cut-scene.

Get ready for the first of many battles with the Harbinger. This creature is a Collector possessed by an alien leader and there are two differences between those two forms - it's more resistant to your attacks and it can fire powerful projectiles. It's crucial that you avoid being hit, because you could die or get heavily injured. Each time you're fighting the Harbinger you'll have to destroy its barrier and then its armor. An excellent idea would be to use a newly acquired particle beam on the mini-boss. Once the Harbinger has lost enough health it'll disappear and new enemies will arrive in its absence. You can continue using the heavy weapon or go back to using standard weapons and powers.

The Harbinger will respawn a few more times and each time it'll take control over a different Collector. An important thing for you to know about is that you can limit this process by quickly eliminating standard Collectors and therefore preventing the alien leader from taking control over them. Each time a Collector has appeared on the battlefield you'll have to drain three of its bars - shields, armor and health. Aside from the mini-boss you should also watch out for assassins, because their attacks will inflict serious injuries. Once it's safe take your time to explore a building located to your right (second screenshot) and you'll have a chance to collect 3000 credits.

You can also explore a much smaller building located in the left corner of the map (first screenshot). Doing this would result in finding valuable power cells. Once you're ready to move on with the mission proceed towards a large gate (second screenshot) and when you're inside a small warehouse you'll have a chance to talk to the Mechanic. Ask him a few questions to find out about the cannons among other interesting things.

Make sure to look around when you're done talking to the Mechanic. Open a safe containing 6000 credits, pick up a med kit and collect 2000 units of platinum from one of the containers. There's also a weapons locker here, however you don't have to use it, because the particle beam is the best weapon you can use right now. Proceed to a new gate (second screenshot) and save your game before opening it, because you're about to take part in a difficult battle.

I would strongly recommend that you order your teammates to remain close to the gate you've just opened, because otherwise they would probably find themselves under heavy fire. Check the situation behind the corner, killing a few standard Collectors and husks. Make sure to choose a particle beam from your inventory as soon as you notice that a new Harbinger has joined the battle. Remember that you'll have to drain three of its health bars and then focus on killing standard Collectors to prevent other respawns.

Aside from the Harbinger you'll also have to watch out for a large beast called a scion. This time you'll be going against a single monster but expect to encounter more of them in the future. Scions are slow but they can create a devastating shockwave which not only stops your characters for a moment but also inflicts MASSIVE injuries. I would strongly recommend using a heavy weapon to kill the scion from a SAFE DISTANCE. If your ammo supplies are depleted use other guns and offensive powers. Once the scion is defeated deal with the remaining Collectors.

You can now spend some time exploring this section of the colony. You should be able to find power cells for your heavy guns and it's crucial to your success that you pick them up. Examine a corpse (first screenshot) to add a new plan for a research project to your database. Finish off by using one of two available stairways (second screenshot) to get to the first floor. You'll find a computer there with 3000 credits.

SAVE YOUR GAME when you're ready to move on and approach a large gate (first screenshot). The gate is closed so you'll have to solve a mini-game. Enter a new area and make sure that the rest of your team did the same thing, because the gate will close itself in a few seconds. You must now begin attacking three new scions. Remember about two things here - you must keep moving instead of occupying a single spot and shoot at the scions from a larger distance. This also applies to the rest of your team - keep them safe so you won't have to use medi gels.

Keep attacking the scions until they're all dead and then take a defensive position in one of the corners of the map. There are also a lot of husks in the area, but you should be able to kill all of them without having to movie. Look around the area to collect power cells and a med kit (only if needed!!). In order to proceed with the mission you must approach a large communications tower. SAVE your game before interacting with the computer, because you'll soon take part in the most difficult battle of this entire mission. Before the battle even starts you'll have to solve a well-known mini-game which shouldn't be a big problem.

Ignore what the game says , because the tower doesn't have any energy bars and you won't have to remain close to it. Instead move back to a small bridge with a concrete wall where you've collected one of the med kits (first screenshot). Set up defensive positions here (along with the rest of the team) and start attacking enemy units. Naturally you have to special attention to the Harbinger and don't forget to kill Collectors in his absence so it'll be more difficult for the alien leader to return to the battlefield.

You'll probably have to kill the Harbinger at least a few times and more Collectors will show up each time it's been defeated. Use your standard guns on them, because you shouldn't be wasting power cells. Be careful, because a large group of husks will soon appear on the bridge (second screenshot) and you'll have to prevent them from making a surprise attack.

Keep fighting the Collectors until you're rewarded with a cut-scene informing you about a boss called a Praetorian showing up on the battlefield. The first thing you should know about is that you'll have to leave cover and start running, because otherwise the boss would have an easy time killing you and your teammates. Don't forget to keep shooting at the Praetorian as you're constantly changing positions.

The objective of this boss battle will be to continue damaging Praetorian's shield so that it loses them and exposes its armor. You'll have to be ready for that to happen and immediately start using a heavy weapon to damage the armor. You can't wait for too long, because in a few seconds the shields will go back up and you'll have to start the entire routine from the beginning. Switching weapons depending on the Praetorian's status will be one of keys to success here.

Keep repeating actions mentioned above until Praetorian loses all of its armor and explodes. You can now watch several cut-scenes. The first scene will feature the main character talking to the mechanic and then depending on the choices you've made in the first game (imported character) or depending on Shepard's gender (new character) you'll talk either to Ashley or Kaidan. Sadly you won't be allowed to convince your friend (or lover) to return with you to the Normandy, because he or she won't support what the Cerberus is doing. Wait to be transported (alone) back to the space ship where you'll take part in a debriefing with an Illusive Man. He will give you locations of other potential crew members, suggesting that you should find them.