Part Two as a whole has presented technical problems for Hugo. Its plot comprises only three events: Valjean's escape and rescue of Cosette; his flight from Javert; and his discovery of a new refuge in the convent. This is very little action to stretch over nearly 300 pages, and Hugo uses various devices to maintain the reader's interest: cumulative suspense, deliberate mystifications, and unexpected dramatic confrontations only later explained in flashbacks.
When Jean Valjean comes to the inn, there is no real reason why he cannot simply present Fantine's note and take Cosette away directly. Instead, Hugo has him approach the problem in a subtler manner so that for several chapters the reader does not know whether he will succeed in rescuing the child or not. Interest is sustained, and the rescue when it comes is much more emotionally satisfying.
Hugo also deliberately mystifies us at three points in Part Two. Valjean falls from the mast at Toulon, but it is a long time before we are quite sure that he has survived and made good his escape. Boulatruelle suspects a man of burying treasure in the woods, but again we do not know for sure that it is Valjean and that he has secreted the wealth he gained as M. Madeleine until much later in the book. And finally, the strange sights and sounds Valjean sees after he has climbed over the wall into the convent garden are deliberately chosen to alarm and puzzle us, and to pique our curiosity.
The flashback is a legitimate dramatic device, almost as old as the novel itself, and Hugo uses it here and in many other places in Les Misérables to good effect. To explain Javert's appearance immediately when he enters upon the scene would be to weaken all the dramatic effect of his irruption into Valjean and Cosette's peaceful life and would destroy the unity and steadily mounting suspense of the discovery-chase-escape sequence. As it is, crisis follows crisis until Valjean disappears over the convent wall; then, satisfied that he is safe, we are prepared to hear an explanation of Javert's presence.
The suspense in Chapter 8 is also very effectively maintained, and the working out of a complex criminal escape plot against the background of a convent also gives Hugo an opportunity for one of the dramatic contrasts both he and the reader enjoy.
