Would something like this work (at least for the interest check) or do you think I need more details?

1) Heroes have been in the public light for a decade max.  Your character can be a newcomer to the heroics/villainy scene or a seasoned veteran (or anywhere in between).

2) The idea of mutants is common scientific knowledge.  What are human-mutants relations like at the moment?  How did "mutant-kind" come into being?

3) S.H.I.E.L.D. is an active spy organization that monitors superhuman activity.  Will they work from the shadows or will they be more public about their actions? 

4) A group of heroes have relatively recently banded together to stop a threat that no single hero could handle.  What threat did they face?  Who is part of this team?  What are they called (Avengers, Defenders, Ultimates, etc.), is up to you.