When I was child I was picked on fairly often (glasses + braces + skinny + athletically disinclined + funny name = easy target) and for years my fantasies were filled with the ways in which I would seek my revenge. Cache is a story about childhood injustices that have never been forgotten and bubble strangely to the surface decades later - highlighting how narcissistic pranks can alter a life course. Or can they? Can we really trace the current state of our lives to one or two defining moments in our childhood? "I am this now because you did that to me then." We do not start our lives on equal footing and with each day encounter situations which may amplify or amputate our chances of success - in whatever way to determine to define it. Cache does a nice job of subtly exploring these emotions - from the p.o.v. of a man whose childhood decisions have come back to haunt him.
Don't expect the story to end all neatly and nicely finished.
Do expect Juliet Binoche to look amazingly French.