In TVB's latest psychological crime thriller, A Great Way To Care II, one particular character stands out.
Plucky undercover cop Lam Chung Yan's life resembles a roller-coaster ride, with dramatic twists and turns.
At the start of the television series, she disguises herself as a chain-smoking, foul-mouthed prostitute to nab drug mules. But by the end of the 25-part show, Lam is a mad schizophrenic wreck on a serial killing spree.
Lam is played by acclaimed Hong Kong actress Tavia Yeung, a two-time winner at TVB's annual Anniversary Awards. She bagged Best Supporting Actress in 2008 and Best Actress last December.
Even for someone who has been earning nods for her versatile acting chops, getting into the psyche of Lam was no walk in the park.
In a phone interview with local reporters on Wednesday, the 33-year-old star recalled the filming as "draining".
"It was really tough, especially as my character's mental state became more and more unstable," said Yeung, who took our call while shooting new period drama, Property Protector, at TVB City at Tseung Kwan O New Town, Hong Kong.
"During the filming for A Great Way To Care II, I became too immersed in my role and was kind of depressed for a while.
"I didn't sleep well for many nights and very often, I'd wake up the next morning, shuddering at the nightmares I had of myself killing people."
A Great Way To Care II, a sequel to 2009's successful A Great Way To Care, is showing on weeknights at 9pm on VV Drama (StarHub Ch 855).
It also stars Hong Kong actors Alex Fong, Yoyo Mung and Edwin Siu as psychiatrists who help the police solve bloody crimes, the bloodiest of which is committed by Yeung's character.
Yeung said the greatest pressure came from her character's "personality shifts".
"The most difficult part was those constant 'jumps' in her behaviour.
"One minute, I could be shooting a scene where she is a normal policewoman, then the next minute, she goes all crazy."
With a chuckle, Yeung said that, thankfully, in real life, she is "extremely jovial", so when filming finally wrapped up for good, it didn't take her long to emerge from her character's dark, twisted world.
"Coincidentally, those actors playing my fellow cops are my good friends," she said.
"When we're off-camera, we will chit-chat and laugh a lot. I believe that helped me in not sinking in too deep into Lam Chung Yan's subconscious mind."
For all her character's evil-doings towards the end of the show, Yeung hesitated to call her a villain.
"There is still a human side to her. It's quite unlike my concubine character Yiu Kam Ling in (2009 costume drama) Beyond The Realm Of Conscience, whose evil side was quite apparent," she said.
"In a way, I'm glad that A Great Way To Care II highlighted the plight of people suffering from schizophrenia. It's a very real mental illness."
Hard-hitting onscreen performance aside, Yeung is basking in her hunky-dory romance with Hong Kong actor Him Law, who at 28, is five years her junior.
The pair reportedly hooked up after starring in TVB's 2012 hit medical series The Hippocratic Crush.
Last September, they weathered one of their biggest scandals when they were caught by Hong Kong paparazzi in what looked like a compromising position in Law's car.
Law told reporters last month that he "hoped to start a family by 35".
When quizzed if she was willing to "wait" for Law to pop the question, Yeung chuckled and replied good-naturedly: "Everyone's ideal age to tie the knot is different. Who knows? I might want to get hitched only when I'm 40 and you'd have to ask (him) if he is able to wait for me."
She added more seriously: "On the question of marriage, the two of us are letting nature take its own course. Right now, work is top priority."
Should she decide to settle down though, Yeung promised she would not keep the news hush-hush. "I would love for the media to congratulate me," she said.