I study here <a href=" http://framedintatnuck.com/writer-paper/ ">written essays online free</a> If a viewer comes to the new ABC action-adventure drama &ldquo;Marvel&rsquo;s Agents of S.H.I.E.L.D.&rdquo; with no prior knowledge of its universe and mythology beyond the awareness that it is related to the superheroes of the mighty box-office world of &ldquo;The Avengers,&rdquo; it might seem strange that none of the main characters are, in fact, superheroes.