Place The First Beacon

After watching the cutscene where the game introduced you to the new character, Brand, you will have a conversation will all of your team members about the mission.
After the cutscene is completed, you can explore the first place for some ammo and health that are hidden in a small container house and behind some wooden planks. Follow the path where you will end up in a new area with new enemies you have to kill.
After you have finished them, you should not explore further, but instead try to open the gate door to get a speech with your team members. Now you have to find a key to open the door.
Find The Key
To find the key, simply go to the left of the area and enter another container to get the key and have another conversation with Kenny.

While trying to get back to the door to open it, you are being attack again by some monsters. Deal with them and then try to open the door with your new key. After that follow the path a bit.
The Kleer
Now you will encounter a new classic enemy, The Kleer. So change to your double barreled shotgun and wait until the Kleer is near you and shoot! He should be down with one shot.

Key To Success
Continue the path until you find a side mission. To get the key to open the door to the supplies, you should go to the left side and enter a new area.

Now some vampires will attack you. After dealing with them, exit the area and follow the path down. Of course, you are being attack here as well. The enemies are on the cliffs, so keep a look-out. Go to the middle of the lake where you find some burning keys. Grab them fast, so you don’t get burned!

Now a lot of very nice people try to kill you. Scrapjacks, Gnaars and some fire dudes want to annihilate you. But you are better than them so show your skill and kill them as quickly as possible. After doing that, go back up where some Processed are trying to kill you.
Go back all the way to the locked door and unlock it. In this room you will find some supplies. Continue the path until you find on the left side a secret building that you can enter and explore. It is not required tho. You will find some enemies there.

Go back to the main path.
The Red Line
On the main path you should find a container with a letter on the desk. Read it and automatically take another key, so you can start another side mission.

Just follow the path to the right with all the blood on the floor until there’s a locked door. You can open it up with your key. Now there’s are huge open area with some Processed enemies tossed around. Kill them and continue the street until you find a parking area with some building. Kill all the enemies and go to the marker to complete your side objective and pick up the new gadget.

Now go back all the way where you have started the side mission. You will be attacked on the way of course.
Aludran Reptiloid
Continue the path for the main mission until you have to kill some Processed. After that, try to install the first beacon. Now a wild cutscene appears where you will learn that Sam wants to eat some bacon. Another enemy, the Reptiloid gets introduced too. His projectiles will hunt you until they explore after some time, so you better watch out.

Kill all the enemies in this area until none are spawning anymore and then go to the left side. Go down and then to the right and in this corner pick up the health. An enemy appears, pick up the other health items and kill all the spawning enemies. Continue this until some big dude spawn outside with a lighting strike. But be careful, he shoots really fricking fast.

After you have killed him, you will get some health gadgets. Continue with the normal path. Now Jones will talk to you that he has reached his destination. Walk a bit further, and you will get a skill point.
Skill Point
Open the box to get a skill point that you can use immediately.

Now collect some ammo and armor that’s lying around, and then you will get introduced to another enemy.
The Zealot
The Zealot is a new enemy in the Serious Sam franchise. The cutscene you will watch shows you the attack of the enemy.

After the cutscene ends, the Zealot will run to you and try to attack you. If you want to kill him, you can’t do it the classic way. First you have to trick him and dodge his attack. Then get around him fast and shoot him in the back.
Continue down the road and some more Zealots will come to attack you. Follow the path where you have to fight some more enemies until you enter an area where you are locked down until you kill all the enemies. So do that.
Leaving the area will get you some new conversation with Kenny and a new area where you can basically just run through and dodge all the enemies, or you do it the classic way, kill them all. Then jump down to enable some more enemy spawns.

You should take care of them all because there are a few really powerful enemies that can reduce your health drastically.
Continue the path and the Professor will talk to you again and enables a new side activity that you may do later. Now you will find a new toy to play.
Rocket Launcher
This authentic ancient roman rocket launcher will indeed bring you great joy.

Continue and some skeletons will spawn. You can use your new rocket launcher on them or use your other weapons to save some rocket ammo. If you now go left you can enable a secret with a vampire. But be careful, he is really powerful.
Now you can decide if you want to do the side mission or not. If you want to do it, walk the right path.
Amateur Archeology
Doing this side mission will get you some nice Time anomaly gadgets where you can slow time.
You will enter a bigger area where you should kill all the aliens and then go down to the excavation area. You will find some interesting stuff there like a letter. Open the box to get the gadgets and complete the side objective.

Now you have to get back all the way while fighting more enemies and continue the normal path and do the main objective planting the beacon. Hand out some bullets while you are at it and some more Kleers and Bulls will attack you.

After taking care of all of them, the door will be unlocked, and you can continue the normal path. Collect some ammo that lying of the right side and continue the way while fighting some easy and strong enemies. After you have dealt with all of them, you should enter the amphitheatre. A cutscene come up.
Boss fight: Khnum
In the cutscene, you will see where Jones was all along. In the captivity of a Khnum. Sadly he dies immediately in the cutscene, and you are not able to rescue him. Now it’s time to fight.

The Khnum has various attacks which includes throwing fireballs at you and running towards you. It also depends on your difficutly setting how many fireballs he throws at you and how difficult it is to dodge them.
Just shoot everything you got at him and dodge his attack, and you will kill him pretty easy. After killing him a new cutscene appears, where the volcano explodes.

With the end of the cutscene, you also end the level “Four Horsemen of the Apocalypse”.