This study offers the first comprehensive exploration of the musical and sonic dimensions of The Decalogue (1988), directed by Krzysztof Kieślowski, with music by Zbigniew Preisner. Through close analyses of all ten episodes, it argues that these operate as a fundamental narrative and symbolic force, shaping meaning, emotion, and reflection. Adopting a three-level analytical framework, the study examines music and sound at the level of individual episodes, musical scenes, and the series as an integrated whole. Particular attention is given to musical motifs, sonic sinthomes and omens, silence, and symbolic structures, including various forms of duality that permeate the cycle. On this basis, the study proposes that The Decalogue can be understood as a distinct musical-cinematographic cycle, unified by complex sonic organisation and coherent aesthetic principles. Combining musicological analysis with theoretical reflection, it offers a new perspective on The Decalogue and contributes to broader discussions of sound in television narrative.