How does the author use foreshadowing in Silent Snow, Secret Snow?

In the opening passage, Paul's shifting view of reality as the narrative develops; and the passage itself, foreshadows the end of the story. The simile—"it was as if, in some delightful way, his secret gave him a fortress, a wall behind which he could retreat into heavenly seclusion"—changes from a comparative device here to reality for Paul. This kind of simile, which Aiken uses repeatedly, becomes, an indicator of Paul's vision as it becomes increasingly snow laden.