Two teams. 1 attacking, 1 defending.
Attackers win if they plant a bomb at either targets A or B, defenders win if time runs out or bomb is defused.
Either team can also win if all members on enemy team are killed. No respawning.
First to win 4 rounds wins, switch roles as attacker/defender after 3 rounds.
It is a fairly camper friendly game mode, but it's also probably the most adrenaline-inducing and realist game mode, especially when playing it in HardCore mode.
There's also,of course, the 500xp/kill and 1000 for planting/defusing the bomb
I would really recommend playing it, takes a while to get used to, but well worth it.
Always have Ninja on