‘Secret in the Box’ Brings a Notorious Hong Kong Crime to Screen

In December 1974, the body of 16-year-old Pin Yuk-ying was found in a cardboard television box on a pavement in Happy Valley. Au Yeung Ping-keung, a married father who worked at a nearby ice-cream shop, was convicted of her murder in 1975 — Hong Kong’s first murder conviction without eyewitness testimony, relying on forensic evidence. He maintained his innocence for years but reportedly admitted the killing in 1989; the circumstances of that admission and aspects of the investigation have continued to attract scrutiny.

Writer Frankie Tam Kwong-yuen’s solo directorial debut, Secret in the Box (紙盒藏迷), takes inspiration from that case. In 2026, when true-crime series, films and documentaries rack up millions of views and Hong Kong continues to revisit its colonial history, what is Secret in the Box really about?

“I think it’s about time,” says Tam, perched on the edge of a sofa. Beside him, producer Philip Yung Chi-kwong is reclined and unbothered by the buzz in a hotel room commandeered by the press. “Time alters memories and memories alter perception.” 

Yung expands on the idea: “Belief. Where does it come from and how do we justify our own? What’s behind our beliefs?” Veteran actor Patrick Tam Yiu-man, who plays the detective investigating the case, offers a concise answer: “People will always believe what they want to.” On Yung’s other side, Edan Lui Cheuk-on of Mirror, cast against type as another suspect, has a more philosophical take. “It’s about decisions. Choices,” he says. “My character’s decision makes this whole thing happen.”

But it’s star Zhang Songwen, who plays Szeto Wai-ping, the character inspired by Au Yeung, who brings those ideas together. “The truth about that night will never be uncovered,” he says. “Szeto’s memories may have already fooled him into believing something different.” Secret in the Box begins in 1974, but its themes of perception becoming fact resonate today — something Tam calls “fate, or kismet.”

A notorious crime

The film had its world premiere at the Shanghai International Film Festival in June, where Zhang won Best Actor in the main competition. On this afternoon, Tam, Yung and the film’s leads are preparing for its closing-night screening at the Hong Kong Summer International Film Festival. At least 15 handlers, managers, make-up artists and assistants are crowded into a suite at FWD House 1881. There’s noise and clamour all around, but Yung remains the calm star around which everyone else orbits.

Tam traces the film’s genesis to 2015, when he saw Yung’s Port of Call twice on the same day. At the time, he happened to be working on a film set across from Yung’s office. “So I went and met up with him, and asked him if I could look at the script,” he says. Impressed by what he read, Tam offered to work on Yung’s next project.

Despite directing across genres — most recently the Lunar New Year comedy The Snowball on a Sunny Day — Yung has returned repeatedly to crime stories in Port of Call, Where the Wind Blows and 2024’s Papa. Tam joined the team when he co-wrote Ho Cheuk-tin’s legal thriller The Sparring Partner (2022), which Yung produced. Both filmmakers admire David Fincher and his stylised explorations of humanity’s dark side.

“I never intended to direct [this],” says Yung. “We’re both fans of David Fincher, and everyone talks about Se7en and Gone Girl, but his masterpiece for us is Zodiac, and we wanted to make a Hong Kong version of Zodiac.” Fincher’s 2007 film follows a cartoonist’s obsessive investigation of the San Francisco serial killer over two decades.

In Tam’s reimagining, Szeto Wai-ping (Zhang, also seen in Jonathan Li’s Dust to Dust) is closing his ice-cream shop one rainy night when teenager Shek Sin-ying (Sabrina Ng Ping) asks to use his phone. They argue and she wanders off. Before he knows what has happened, police led by detective Chan Cheung (Patrick Tam) arrive to arrest him. Szeto is convicted and imprisoned. After the case closes, Chan begins to doubt the investigation, and both men spend the next two decades seeking to clear Szeto’s name. Shek’s boyfriend, Wong Ban-wing (Lui, Chilli Laugh Story, Hong Kong Family), emerges as another possible suspect, but neither man is heard. Secret in the Box bears the aesthetic hallmarks of Yung’s films: location shooting in parts of Happy Valley and Shau Kei Wan that retain traces of the past, tactile production design by Eddie Lau Kwok-on (Septet), textured colour grading and in-camera effects from cinematographer Joseph Leung Yau-cheong, with input from Radium Cheung, to evoke the grainy imagery of the 1970s.

While the visual language recalls The Sparring Partner, Tam favours personal drama over police procedure, much as Yung did in Papa. “We wanted to explore how different characters’ lives were impacted by this case. It spanned 20 years, so people changed,” he says. “During production people often asked us ‘Did he really do it?’ I think that sums up what the movie is about.” Fittingly, Secret in the Box ends on an ambiguous note, open to personal interpretation.

The film also recalls Michael Mann’s crime classic Heat: the detective and the suspect circle each other but meet face-to-face only once. Patrick Tam and Zhang built their dynamic on trust, stillness and close attention to each other. Their jailhouse meeting was the final scene they shot together.

“When I first heard [Zhang] was cast as Szeto I was very excited about it; I thought it was perfect,” says Patrick Tam. “It demands a very seasoned actor, and for that particular scene, I let him take the lead. It’s like playing football. You’re trying to serve something to each other you can both use.”

Hong Kong’s Val Kilmer?

That comparison also speaks to how fundamentally performance-driven Secret in the Box is. Patrick Tam’s recent roles in We’re Nothing at All and Finch & Midland have placed him among outsiders and men at difficult crossroads. He sees a similar tension in detective Chan: “Actors are often marginalised. So when you play marginalised characters you understand that struggle to survive. When the story starts [Chan] believes Szeto is the murderer. But he’s different from his peers. His change of heart and the passion to uncover the truth mirrors his need to prove he’s different for those around him.”

Szeto’s evolution and humanity attracted Zhang to the role. “This script is extremely profound, depicting characters who have suffered injustice over 20 years, with incredibly rich inner lives.” Born in Guangdong and long established in mainland China’s film industry, Zhang was keen to take on a substantial Hong Kong film role. “I’m from Guangdong and Hong Kong is a Cantonese film industry. I love the city and I love the Hong Kong movies I grew up with,” he says. Hong Kong cinema faces substantial pressures, but Zhang sees its difficulties in a wider context. “I don’t think there’s a demise or decline in Hong Kong movies. It’s a global change.”

There’s a short debate over which of Patrick Tam and Zhang is Robert De Niro and which is Al Pacino, but Yung gestures at Lui and chimes in: “He’s Val Kilmer.” The self-described “industry newbie” hovers on the periphery until Wong reasserts himself in the case. A philanderer with a drug addiction and little empathy, Wong sits in direct opposition to Lui’s pop-star persona. “Any chance [to take] a role in a film is a great opportunity, so I didn’t come at it with thoughts of what I should or shouldn’t be playing,” he says. 

Still, Mirror has made it important for him to show he can step outside his — and his fans’ — comfort zone. Unlike Patrick Tam and Zhang, Lui faces expectations that he remain present and accessible on social media. “That’s actually an obstacle I have to face. People form an image of me — Edan is a funny guy, he’s an idiot, he’s stupid, he sings all the time — and some will see this and think, ‘Oh, that’s not him.’ I think it’s a journey, and so the more different characters the better.”

Secret in the Box screened at the Hong Kong Summer International Film Festival on 30 August. A general theatrical release date has not been announced.