Paradise Lost Review: Train To Busan Director's New Movie Rivetingly Explores AI's Role In Grief [TIFF]

Paradise Lost is a riveting psychological thriller that uses AI, grief, and a mother’s impossible choice to explore the darker side of human nature. Published Sep 18, 2026, 3:36 PM EDT George is a film critic and journalist with over nine years of experience in the entertainment industry. Beginning as the Co-Creator and Co-Editor of Star Wars Holocron, the most followed Star Wars fan account on Twitter/X, George went on to develop The HoloFiles, a movie and television-focused website with his brother and writing partner Josh. A member of the Hollywood Creative Alliance, Chicago Indie Critics, Online Film and Television Association, and the Internet Film Critic Society, George has covered major industry events as credentialed media, including D23, CinemaCon, SXSW, Fantastic Fest, Star Wars Celebration, Tribeca Festival, and more. He also regularly writes reviews and contributes articles to ScreenAnarchy, BRWC, Film Obsessive, TV Obsessive, and Under the Radar. George's work has been featured in various esteemed publications, including the BBC, Associated Press, Forbes, and The New York Times. Yeon Sang-ho has spent much of his career finding new ways to make genre cinema feel deeply human, whether it be animation, apocalyptic horror, science fiction, or emotionally bruising family dramas. From Train to Busan to Hellbound, his films have consistently used heightened premises to examine uncomfortable truths about people. This year alone, Colony and The Ugly have continued that tradition, with the latter in particular confronting the darker corners of human nature. Paradise Lost feels like another natural evolution of those interests: a riveting psychological thriller that uses mystery, grief, and artificial intelligence to ask what happens when the person we desperately want back is not the one who returns. Making its world premiere at this year’s Toronto International Film Festival, Paradise Lost kicks off with a devastating event. A bus carrying 12 children to camp vanishes, leaving behind only a handful of bodies and a case that eventually goes cold. Among the grieving parents is Ryu So-young (Kim Hyun-joo), who finds an unusual form of solace through AR glasses that allow her to reconnect with her missing son, Sun-woo. For nine years, the virtual version of her child serves as a source of comfort, preserving the idealized child she remembers and allowing her to maintain some semblance of a relationship with him. Then, out of nowhere, the real Sun-woo (Bae Hyun-sung) returns as an adult. Rather than providing the closure So-young has spent nearly a decade seeking, his arrival fractures her world all over again. The real Sun-woo is a cold stranger, while the virtual version needs her more than ever. Paradise Lost Interrogates AI’s Role In Grief In an age in which artificial intelligence continues to develop at an extraordinary pace, there is something increasingly fascinating about stories that ask what makes humans human. Yeon’s film is far from the first to do this, but Paradise Lost approaches that question through one of the most emotionally complicated subjects imaginable: the loss of a child. This makes Paradise Lost an interesting companion to Yeon's recent The Ugly, another uncomfortable film willing to confront harsh truths about human nature. Where The Ugly centers its emotional examination on a father and son, Paradise Lost pivots to a mother and son. Both films ask what happens when familial love collides with realities we would rather avoid. There are also echoes of Gore Verbinski’s Good Luck, Have Fun, Don't Die, particularly in the way it explores the intersection between AI and the grief of losing a child. The technology in Paradise Lost is initially introduced as something intended to help Ryu. However, over time, that assistance becomes dependence. The AI son is no longer simply a tool helping her process grief; it becomes something she relies upon to function. Paradise Lost Compels With Its Central Dilemma Kim gives the film an effective central performance, gradually revealing just how psychologically fragile So-young has become without reducing her grief to a simple explanation. There is an unnerving intensity to the way she interacts with both versions of Sun-woo, and Kim constantly keeps you on your toes, because it is never entirely clear where her maternal devotion ends and her emotional dependence begins. Her performance makes So-young sympathetic even when her choices become increasingly difficult to defend, which is essential to the film's central dilemma. What should So-young do with this crazy situation? Should she let go of the virtual son she has spent years nurturing and become attached to, even though he is essentially an artificial reconstruction of her memories? Or should she accept the supposedly actual son who has returned to her, despite his moodiness, emotional distance, and apparent inability to resemble the child she remembers? There is no easy answer, because neither choice offers the closure she desperately wants. It’s through this impossibly difficult dilemma that Paradise Lost proves most compelling. Yeon does not simply ask whether AI can imitate a human being. Rather, he queries whether imitation even matters when the person using it is emotionally incapable of letting go. If an artificial version of someone provides genuine comfort, does it matter that the relationship isn't real? And if a real person returns but fails to satisfy the emotional expectations we have built around them, what does that say about our understanding of love? These are all questions people in the real world should be having, especially as AI continues to advance and play an increasing (and potentially unhealthy) role in people’s social lives. Unfortunately, the resolution doesn't quite land with the same force as the questions that precede it. The film builds an intriguing psychological and emotional puzzle, but its eventual answers feel less satisfying than the mystery surrounding them. In some ways, that may be fitting for a story so preoccupied with the ever-illusive nature of closure. In a world where people increasingly turn to AI to meet emotional needs, Paradise Lost leaves us with a somber warning about what happens when something designed to help us process our emotions and get through life adaptively becomes the very we depend on and can no longer live without. Paradise Lost premiered at the 2026 Toronto International Film Festival. Release Date September 13, 2026 Runtime 101 minutes Director Yeon Sang-ho Writers Ryu Yong-jae, Yeon Sang-ho Producers Yoomin Hailey Yang Cast Kim Hyun-joo Ryu So-young Bae Hyeon-seong Ryu Seon-wu