This article aims to rethink the phenomenon of therapeutic resistance: from its perception as an obstacle to understanding to a diagnostically valuable «text» of the client’s life script. The goal of the study is to develop and describe a reproducible TDS (Transactional-Diathesis-Script) algorithm, allowing therapists to analyze client behavior in the office as a multilayered structure. The study was conducted through theoretical modeling and in-depth qualitative analysis of a single clinical case (120 therapy sessions with a 32-year-old client, diagnosed with F43.2 and F60.7). The theoretical framework was based on transactional analysis, the diathesis-stress model, and the epigenetic metaphor. A four-step algorithm is proposed: observation of behavioral patterns; a TA hypothesis (script prohibition, defense mechanism); a biopsychosocial hypothesis taking into account family history and vulnerability; and an integrative formulation of an early decision. The article provides a table of correspondence between behavioral manifestations (lateness, intellectualization, devaluation, silence) and script beliefs and prohibitions. A clinical example demonstrates how the algorithm enables the transformation of resistance into an exploratory dialogue. The TDS algorithm changes the therapist’s perspective: resistance becomes not a battlefield, but a key to the core of the script. The model can be useful for practicing psychotherapists, especially in the transactional analysis modality, and in training programs.