Chapter 1- Ghost Four

Nico Di Angleo, Percy Jackson, Jason Grace, and Leo Valdez are the only demigods left, Camp Half-Blood and Camp Jupiter are gone. The gods gave them a gift of staying alive and living as the last demigods. What happens when the Ghost 4, who protect America and slay the really bad guys (like Batman), are found by S.H.I.E.L.D and the Avengers?
So I was thinking about this and wanted to make it. It might not make some sense in the beginning but I will try and make it make sense. Hope you like it.