Wikia

Hostage rescue (cs) is a game mode where the main objective for the Counter-Terrorists is to rescue the hostages. Terrorists must prevent them from doing so. Hostage rescue maps are prefixed with "cs". Generally, the hostages are placed near the Terrorist spawn. To rescue the hostages, the Counter-Terrorists must interact with them (by walking up to a hostage and pressing the use key) and lead them to the hostage rescue zone, usually located near the Counter-Terrorist spawn. The secondary objective, which also secures a victory for either team, is to eliminate all members of the opposing team. If the round time expires, the Terrorists win by default.

If all the surviving hostages have been rescued, and that number is at least half of the initial hostage count, the Counter-Terrorists will win, and each Counter-Terrorist is given a monetary reward. The game mode may effectively become a 'terrorist hunt' if all hostages are killed. Killing a hostage by either side usually incurs a large amount of stiff penalty in cash, and will sometimes garner a slaying, kick, or ban from the server.

When a Counter-Terrorist begins interacting with the hostages, they will be rewarded a small sum of cash. Upon successfully escorting a hostage to a rescue point, a much greater sum is awarded to the individual Counter-Terrorist.

In Counter-Strike Condition Zero, there was another way for the Counter-Terrorists to win. In this situation, hostages are given the ability to escape on their own and reach the hostage rescue zone, if they do not sense the presence of a terrorist and they do not encounter a Counter-Terrorist. If the all the hostages are able to reach the rescue zone by themselves, the game will announce "Hostages have escaped" instead of announcing the usual statement "Hostages have been rescued". (Online mode only)

In Counter-Strike: Global Offensive the gamemode has recently been revamped. Now only having two hostages, compared to the normal four. The Counter-Terrorists have to pick up the Hostages and carry them to the escape zone, only one needs to be rescued. While carrying a hostage the Counter-Terrorist is slowed but an extra minute is added to the clock to compensate for this.