What If … Captain America was the Shield Hero?

Steven Rogers. Student at S.H.I.E.L.D. Academy and one who goes by the name "Captain America". What was supposed to be a normal night of studying went down the drain once a book about "Cardinal Heroes" and whatnot makes its way into Steve's hands. Now he's told that he has to save the world for the "Waves of Calamity". Shouldn't be a problem for a Hero-in-Training, right?