A Hundred Billion in Debt, Out of Nowhere!

A woman with a terminal illness leaps off a cliff in despair and crashes into an alien research vessel! The upright, magnanimous alien researcher repays her evil with kindness, repairs her body, and proposes a deal: Over the course of fifty years, without changing Earth's technological or cultural development, she must achieve one hundred small goals in a reasonable and legal way, earning him ten billion! She must send a robot to Europa (Titan), mine the X mineral there, repair the research vessel, and help him return to his home planet!