For several days the possible contents of this mysterious envelope prey upon Anka's mind, a conflict between personal desire and moral obligation. While a visit from one of Michal's old college friends (Andrzej Blumenfeld) fails to shed any light upon the matter, a dusty photograph of her mother gives some intriguing clues. Perhaps it's a personal message from her long-dead mother, something she was always destined to receive, a secret from beyond the grave? Inevitably giving in, Anka slices open the envelope to reveal a second letter (a bit like a Russian doll), addressed directly to Anka in her mother's handwriting. When Michal reappears, she confronts him with the contents, an irreversible move. From this moment on, their relationship shifts onto a new footing - forever.
To a greater extent than the other members of the Dekalog series, Dekalog 4 touches upon forbidden and taboo thoughts. After having lived with Michal for her entire life, the discovery that he may not in fact be her real father places a whole new interpretation on their relationship for Anka. Initially bitter and betrayed, angry that this information wasn't revealed earlier, Anka finds herself deprived of vital stability. However, from Michal's perspective there was never a good time to pass on her mother's communication, especially when he was unaware of the contents. A suspicion had always existed though, colouring his behaviour. As this tangled web of emotions is parted, one particular question stands out; would a sexual relationship count as incest?
Both Biedrzynska and Gajos give excellent performances, judging sensitively the nuances of their characters and how they change throughout the film. Successive revelations alter the situation time and time again, with the surviving core element being that Anka and Michal love each other (though the form of their love evolves). During this state of flux, the roles are never less than believable. Their torment is almost physically tangible, especially when the many barriers have been pushed aside and emotional nudity remains. In this condition all queries are answered candidly, whatever the effect.
Dekalog 4 illustrates the clarity of Kieslowski's comprehension of the problems facing humanity and how best to translate these onto the screen. This ability to both understand and interpret is rare in itself, even more so when the central themes of this episode are considered. Sexual love between people of disparate ages is a thorny topic alone, so when this is combined with family structures, the resulting amalgam can be explosive. Despite this backdrop, Kieslowski is fair in both his writing and direction. Whatever your initial reaction, Dekalog 4 is persuasive; it forces you to feel and think about what is being shown, while avoiding easy solutions.