1981’s X‑Men: Days of Future Past was a two-part story that first appeared in the comics X‑Men 141 and X‑Men 142. Chris Claremont was credited as writer, John Byrne as artist; the pair shared plotting credit.
In the unimaginably distant year of 2013, New York’s Park Avenue is a vast slum, as is New York itself. Indeed, New York’s condition reflects the dismal state of America as a whole: an economically declining dictatorship whose population is regimented by the giant robot Sentinels along eugenic lines. Put simply, it’s mutant versus human!