It's Paris in the springtime, in 1968, and the students are revolting. "Matthew" (Michael Pitt) is visiting from the USA and he encounters the siblings "Theo" (Louis Garrel) and "Isabelle" (Eva Green) with whom he shares a fascination with movies. They invite him to their home for dinner just as their parents are heading off on trip. It's clear to the visitor that these two have a curiously intimate relationship. Not incestuous, but not a kick in the shirt off it. What now ensues sees "Matthew" ensnared in their games that have basically few holds barred - an orgy of the body and the mind…