I´m a huge fan of Hitman, I really loved the first game and played it to death even though the story was weak at best and some levels were pretty bad(the djungel!!).
I liked the demo of Hitman 2, but it was way to easy just to kill EVERYONE in the entire level and then walk off.
Oh, if I can try my best at guessing the story of the game, father Vitorio is actually kidnapped by the organization that wants you to kill for them, so they just pretend he´s located in the house of Victim nr.4, you´ll go there, kill people and "oh no´s, the padre is gone and located on the next level."
In the end you are of course going to kill the people behinds this etc. etc.