Complex sentence: Cut to the present day and Münchhausen II is trying to fulfill his father's work--to summon the Lord of Chaos--but to make sure it will work this time, he needs a human sacrifice.
Split into simpler sentences: Cut to the present day and Münchhausen II is trying to fulfill his father's work--to summon the Lord of Chaos. But to make sure it'll work this time, he needs a human sacrifice.