Sonata for piano is an intense and heavy work. Although many of his works have prominent piano parts (for example, Six Meditations and Alone by a Stream in Arcadia), this is Mills' first major work for solo piano since Lumen, Nox, et Imagines: In Memoriam Inspiratricis (2003). The sonata is in three movements.

The first, םירבדה הלא (elleh haddebarim, ‘these are the words’; see Deuteronomy 4), is tonally centered on G-sharp and is rhythmically driving, giving the sense of a relentless pursuit. The eight-note symmetrical scale of G-sharp, A, B, C-sharp, D, D-sharp, F, G (a projection both above and below the tonic pitch of a minor second and minor third with the entire scale reflected around the tritone) helps to unify the tonal material. It is percussive and motivically tight. The otherwise unyielding 6/16 meter is interrupted thrice with three tolling chords. Halfway through the movement a three-voice fugue begins; the contrapuntal manipulations continue for some time until they finally break down and the opening material returns in a brief recapitulation. The tolling figure then appears once more with a massive rush of intervening chords from the depths of the keyboard before the movement ends with a last powerful statement of the opening theme.

The second movement, ti estin alhqeia (ti estin aletheia, ‘what is truth’; see John 18) opens with a soft and slowly-repeated B-flat which continues throughout the majority movement. It is a bleak and hopeless landscape. Even when the pitch level of the repeated B-flat finally changes, the same inexorable rhythm continues on with only two respites in the entire movement. The sense of desolation stands in stark contrast to the frantic chase of םירבדה הלא. The music builds slowly in a massive 40-bar crescendo only to die away back to the same emptiness whence it began without any arrival. It ends as it began, with a lone tolling B-flat slowly marking the passage of time.

In amen dico tibi (‘truly I say to you’; see John 14), the oppressive heaviness of the second movement is finally lifted. It opens with and is tonally centered on the E-major triad. Because of the extremely slow tempo, the broad, resonant chords, the simple, floating melodic lines, and the conspicuous absence of activity so present in the first two movements, this final movement has a sense of timelessness to it. After the opening chords, the explicit E-major chord disappears, hinted at and expected, but not heard. Not until the movement is mostly complete does the opening progression return, finally arriving on the E-major chord accompanied by the same tolling harmonies from the first movement but in a new light. This is the climax of the entire sonata, the true point of arrival encapsulating all that came before it. The piece ends quietly with a repeated B over the E-major harmony, harking back to the rhythmic motives of the preceding two movements.

Sonata is dedicated to Charis Diamantopoulos, pianist and friend, whose elegance and grace have been truly beautiful and most appreciated.