Basically Loki is living with the Avengers for penance for his crimes or something like that. He's helping clean up a mess in New York, he turns to talk to Thor and gets shot in the chest by one of his minders because his brother was killed in the invasion or something and the people of shield didn't check into it.
So after he's fixed up and everything Bruce was talking about how he has like, 6 chambers in his heart and an enlarged heart and Clint laughs at the irony, then Thor explains that because he's a Frost Giant his hearts supposed to be like that so that they can survive in the freezing temps of Jotunheim.
And that's all I remember from that story. Any help would be appreciated!