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Behind (zs_behind) is the second chapter of Zombie Scenario: Season 3 in Counter-Strike Online.

Official Description[]

David Black is trying to contact Norman directly after receiving an urgent request from him.

This is David from AFC. Answer me, Norman! Hmm.. It seems like the contact has been cut off. This can be critical, we need to find his location now and move out!

They tracked the last location of contact and arrived at an isolated town. This town is deserted and is only accompanied by sandstorm. This is the secret entrance of the Vanguard Laboratory.


  1. Upon receiving Norman's rescue request, the AFC Mercenary Group dispatches David Black's unit.
  2. David Black, who was on his way to the entrance of Vanguard's secret base in chasing Norman's last contact, encounters a flood of zombies before he even enters the base.
  3. Black, who thought this quest was a simple rescue task, was puzzled, but attempts to enter the base to carry out the mission. However, it wasn't Norman who greeted them, but an infected, mysterious monster.
  4. CF. The Rusty Scorpion is in the form of a scorpion, and the original armsuit was designed for support rather than military use. It was infected with the Vanguard Company's secret weapon, mainly designed to infiltrate and surprise the ground. Because it is a surprise weapon, it can perform hit-and-run tactical actions such as hiding in the ground, and is known to have a self-repair system.
  5. CF. Judging from the contents of the secret weapon classified document, it seems that research has been conducted to fuse Dr. Rex's Rex virus with Vanguard Company's high-tech military technology. In the early stages of development, it was judged to be successful without any problems, but after Dr. Rex left the Vanguard Company, it seems that the Rex virus got out of the control of the Vanguard Company and became uncontrollable.


Find the secret entrance of Vanguard Laboratory from the town and enter inside.


Bio Scorpion

Taking place in a desert, the players must make their way through an abandoned village to locate yet another Vanguard Contact laboratory. Once there, the players must use the elevator to reach the laboratory's basement level. If they are successful and have made it through the laboratory alive, the players will fight the boss, a machine-like scorpion. For the first time ever, this map introduces David Black and Erika as the guiding NPC.

In this map, the player will face Bio Scorpion as the boss.

Release date[]

Behind was released on:

  • South Korea: 6 December 2012.
  • Taiwan/Hong Kong: 19 December 2012.
  • China/Japan: 19 December 2012.
  • Indonesia: 20 November 2013.
  • Singapore/Malaysia: 20 November 2013.
  • CSN:Z: 23 September 2014.
  • Vietnam: 9 April 2015.


Start point
Davidblack msg
Jpngirl01 msg
  1. David Black: Norman! This is David Black from AFC! Answer me!
  2. Erika: We can’t still get any responses from them.
  3. David Black: Hmm.. we don’t have much choice. Let’s pass by the town and invade Vanguard Laboratory!
  4. David Black: Darn it.. The town entrance is blocked. Erika!
  5. Erika: You will be able to destroy it easily by installing a bomb on the door.
  6. David Black: Fine. Let’s destroy it with the bomb.
After entering
  1. Erika: Zombies are here! Let's fight!
  2. David Black: Is that a sand hole? It looks dangerous, do not get too close to it!
In front of the big hole
  1. David Black: What’s that? Stop everyone!
  2. Erika: It’s a big sand hole! I don’t think we can pass by it.
  3. David Black: The pillar of the buildings look pretty weak. Do you think we destroy it with our weapons?
  4. Erika: It will collapse if we break the pillars. Let’s focus our firepower at the pillars, everyone!
Dead End Swoodt
  1. David Black: This is a dead end swoodt!
  2. Erika: No, based on the coordinate information, VanGuard’s Laboratory is just opposite!
  3. David Black: Umm.. It seems like we can bring down the building by destroying the gas pipe!
  4. David Black: Target the gas pipe and shoot it, everyone!
Secret Laboratory Entrance
  1. Erika: Look at the entrance over there! It is connected with the Laboratory!
  2. David Black: Fine! We will enter now.
  1. Erika: It’s an elevator. I guess we can ride on it and enter the Laboratory.
  2. David Black: Fine, operate it! We will stop the zombies until the elevator arrives at this floor!
  3. David Black: It’s coming down soon! Get into the elevator, everyone! Hurry up!
  4. David Black: Be careful! Zombies are jumping from the top.
  1. David Black: This is a lift station. We will ride on it and move.
  2. Erika: We should defend zombies till the lift arrived!
  3. Erika: Ride on the lift, everyone! It will move soon!
  4. David Black: It’s Venom Guard! Be careful of him!
  5. Erika: Throwing type zombies appeared from everywhere! Be prepared of the explosion!
  6. Erika: Oh no! The shutter is closing! How could we move over to the opposite side now?
  7. David Black: There is an Emergency Release Device on the top. Destroy it!
Boss room
  1. David Black: We are almost there! We can enter the Vanguard Laboratory by passing by this door!
  2. David Black: Let’s move to the entrance of Laboratory, everyone!
  3. Erika: Wait a minute! Where is this vibration coming from? It seems to be coming from the basement!
  4. David Black: What is that!? It looks like a scorpion! Target it and fire!
  5. Erika: It is trying to hide into the soil! Watch out!
  6. Erika: It is taking a defense action!
After boss death
  1. Erika: We almost clear them. What’s going on in the Laboratory?
  2. David Black: We will know it soon.. Let’s enter the Laboratory, everyone!


Title Description Task
A medal given to a person who achieved victory in a battle with Bio Scorpion[Scorpion Chief] Gentlemen, you better be careful when you have a battle in the desert. There are not only invisible enemies. Sometimes, nature is scarier than any other enemies. (Only available in rooms for more than 4 players, easy stage is not included) Defeat Bio Scorpion 100 times.



  • This is the first Zombie Scenario map where a player can fall off the map.
  • There are some types of quicksands in certain areas of the map where if you touch them, they will kill you.
  • Musics in this map were taken from Building Recon, Motorcade Assault, Turn of the Crank and Rise Hard missions from Counter-Strike: Condition Zero Deleted Scene.
  • Sometimes the lift gets bug that it cannot go down after player pressed the button.
  • Bio Scorpion will not receive any damage when it is going to hide in the sands.
  • Afterburn effect will still damage Bio Scorpion even if it has gone into sands.
  • There is a bug where sometimes player can see a Phobos' portrait on the boss health bar instead of Bio Scorpion.
  • This map resembles Black Mesa Inbound, the first chapter of Half-Life.