This study began from Genette's notion that we should organise the analysis of narrative around categories borrowed from the grammar of the verb. It is now possible to be specific about what must be added to a grammatical approach if we are to do any justice to the complex philosophical approaches to the future that we have been exploring, and to the particular valence of the unexpected. We found, in each section of the argument, a tight complementarity between thinking forwards and thinking backwards, that the cognitive functions of prospect and retrospect are difficult to separate, and that surprise has a special power to reveal this complementarity. We explored the metaphorical basis for a profound confusion between the spatial orientations of forwards and backwards in our thinking about time. We found, in Morson's analysis of narrative and freedom, the view that foreknowledge makes us hold the forward movement of experience and the backward movement of explanation together in a double structure, and in Sternberg's narratological account of surprise, the notion that the unexpected arrival from the future springs an unexplained past. In Paul Ricoeur, we found that unexpected events in narrative present a paradox which inverts the effect of contingency into the effect of necessity, turning chance into fate and the accidental into the intended, as well as a circular account of mimesis that shows how this paradox refigures our understanding of surprise in life.