Corrected, I would like to add (with the support of Latin memories stretching a bit far...), for the fact that Graham Greene's novel is singular. The original expression in medias res -- in the middle things, literally, no 'of', which is important -- refers necessarily to the plural. res is the direct object, accusative case. Singular would be rem, thus we need the plural. I think. Never miss a chance to brag; my motto.
Let's see. a, ae, ae, am, a - ae, arum, is, as, is es, ei, ei, em, e - es, erum, ebus, es, ebus (Not one hundred percent on those.) Original phrase: in medias res, into the middle things, accusative plural. My change: in media Quiet American, in the middle [of] QA, ablative singular? I suppose an 'of' could have been included but I unconsciously elided it for comprehension's sake. Worth noting: there seems to be some confusion online as to the literal translation of in medias res. Even wiktionary etc have it as 'in the middle of things' but unless I'm missing a subtlety, adding an 'of' changes the case to genitive (rerum). Only by translating the phrase "into the middle things" is this problem avoided.