A year ago on this blog, I shared this trend about recent popular film music: "When two major triads whose roots are four semitones apart are adjacent, the triad with the root four semitones above is significantly more likely to be the tonal superior." This happens particularly when the two chords have been isolated from other tonal obligations and, without such obligations to gain tonal meaning, instead look toward one another.
In sonata form -- a drama which this drama is within -- the recapitulation is both a return to and a reworking of the material from the exposition. In the first movement of Beethoven's op. 109, measure 62 in the recapitulation corresponds to measure 13 in the exposition. This time, it is a C-major triad that floods our senses much the same way that the D-sharp-minor triad did before. But its corresponding transformation is to an E-major triad, whose root is four semitones higher. The same harmonic conversion is now a homecoming, which I show with an arrow that changes from purple to red.
In measure 13 of the first movement of Beethoven's op. 109 piano sonata, the notes of a D-sharp-major triad fill up most of the register of the piano and our attention with its sonorous and solid proportions, blocking from view much of what had occurred before. Then its firm surface suddenly shimmers and transforms into a B-major triad. To some film-music ears, this is a departure from stability and security: since B is four semitones lower than D-sharp, B is demoted in this two-character drama within a drama. I indicate this visually with a red arrow that fades into purple.
To be sure, this harmonic scheme is rather standard: the sonata is in E, and B is accustomed to its subservient role when E is the tonal sovereign. But local harmonies, together with a future music's chromatic tendencies, enrich this relationship and even offer a guide, however anachronistic, to the work's overall tonal plot.