There are 6 seasons. All out on dvd except for season 6. Kate gets shot in the head by a terrorist named ari in season two, episode "twilight" but you should also watch season three's first two episodes "kill ari pt.1" and "kill ari pt 2". The follow-up on kate's death.
There are now 7 seasons but the 7th hasnt came on yet. I think there are like 150 episodes. Kate was shot in the head by the terrist Ari H. He was trying to kill all the woman in Gibbs team to make him suffer. He tried to kill Gibbs but Ari's half sister Ziva David Shot him. NOw Ziva works for Ncis on Gibbs team.
