Yoo-go the Destroyer

On a post apocalyptic world setting an NPC enlists the PC's to help him finish his father's life's work. Repair of a large to giant robot. PC's have adventures gathering missing components. It turns out though that the reason the father did not finish it is that he realized that it was left by the aliens that destroyed the world's society. When the bot wakes up it reboots the program to destroy the world. Note: I thought this Idea up after driving by a Hugo movie billboard though I have no clue what the actual plot of Hugo is. My plot probably makes for a better RPG adventure.