Swapped In Secret

When Phil (played by Seth Gamble) comes back home, he encounters an unfamiliar woman named Tracy ( Jane Wilde). She shocks him by insisting he is her father. Phil is taken aback and bewildered, intensified when his wife Nancy (acted by Charlie Forde), seems complicit with Tracy.
Nancy discloses a crafty plan whereby she arranged with another household for Phil to experience his filial/stepsibling traits desires, which she learned about from his online browsing history. Phil is appalled and leaves the scene in a furious outburst. Although Tracy is crestfallen, Nancy reassures her that eventually, Phil will come back around.
Subsequently, in numerous occurrences, Phil is enticed into family interactions involving Tracy, despite his inner reticence. As moments pass, subtle indications of Tracy attempting to entice him escalate, playing into his undisclosed inclination. Phil persists in staving off his unfathomable desires, intending to maintain their preservation fictional.
However, the temptation becomes increasingly insistent. Part one evening, amidst stillness, as Phil is drifting off in bed, Tracy enters, slips under the sheets claiming to be haunted by a nightmare. Debatably legitimatized, Tracy endeavors to lure Phil completely, he appears receptive and begins indulging Tracy's effusions of affection, gradually compromising built-up fortitude, ultimately embracing dormant inclinations.
Eclipsed in his permitted excavation, little does Phil discern that Nancy is sharpening a clandestine move for the subsequent feint.