Highlander II in a nutshell:
Louise Marcus: Okay, now let me just see if I can get this straight. You come from another planet, and you're mortal there, but you're immortal here until you kill all the guys from there who have come here... and then you're mortal here... unless you go back there, or some more guys from there came here, in which case you become immortal here... again.
Conner MacLeod: Something like that.
Myself: Are we clear?