You, Luffy and the others has gotten in the Enies Lobby and ready to fight the CP9 Agents to get and save Nico Robin back from them, then all of you has split up and you end up fighting with Kalifa, who is in front of you right now with you staying on the ground, cause of her Devil Fruits powers.

Kalifa: “Coming to save your friend, Nico Robin? Sorry, but this time she should be going to Gate of Justice by now, but for her is should be the Gate of Hell.”

She just like the other CP9 Agents, have no mercy for any pirates, especially someone as dangerous as Nico Robin.