In the beginning, there is thanos gloating over his capture of thor andpaticularly on becoming the first person to own two infinity stones.that gives him immense powers already, but thanos want remaining four stones too and goes forth searching himself or sends out children on pursuit. Whenever they go they leave behind destruction. One of those infinity stones is held byDr strange another by vision( paul battany) a third by a nercenary and fourth lies across a velley that call for supreme scarifce from the person who wants it.