Protesters flooding downtown Hong Kong to stop the Government's proposed extradition law effectively presented the city's leaders with an ultimatum: back down, or risk violent clashes that could be worse than the Occupy movement in 2014.
Thousands of demonstrators gathered in the heart of the financial hub overnight NZT, and some battled with riot police to prevent lawmakers from debating the bill.
Overwhelmingly young, many protesters wore surgical masks to hide their identities and plastic goggles to ward off pepper spray, which police fired sporadically throughout the day, along with tear gas, rubber bullets and bean-bag rounds.
"This is the end game for Hong Kong, it is a matter of life or death. That's why I come," Rocky Chang, a 59-year-old professor, told Reuters news agency.
"This is an evil law."
Hong Kong's Government, led by Chief Executive Carrie Lam, says it has no intention of giving in to the protesters' key demand: scrapping the proposed law that would allow criminal suspects to be extradited to mainland China, among other places.
Lam has argued the bill is a necessary measure to update the city's rules for dealing with individuals facing criminal charges elsewhere.
"I've never felt guilty because of this," she said in an interview with local broadcaster TVB, her voice cracking and her eyes appearing to well up as she insisted she would never betray Hong Kong.
But the protesters managed to scuttle the debate yesterday, and it's now unclear when legislators will reconvene for 66 hours of scheduled discussions before a vote, which was originally planned for later this month.
"This time some people say peaceful protest is useless," said Suki Fung, 24, catching her breath after inhaling tear gas. "People think there has to be more of a fight - otherwise it's useless with this Government."
For the protesters, the extradition law represents a line in the sand: a dramatic undercutting of local autonomy that will end Hong Kong's status as a safe haven for dissidents fleeing the mainland.
They have drawn the support of US lawmakers like House Speaker Nancy Pelosi, who called on Congress to reassess Hong Kong's special trading status - a move that risks damaging the city's reputation and pushing more multinationals to locations like Singapore.
"We must fight peacefully, and we must continue," opposition lawmaker Claudia Mo told the crowd. "With all your presence here, we can do it together."
The marchers were well-organised and coordinated, dropping umbrellas from an overhead walkway to provide protection from police and the rain for those in streets below. Others tied metal barricades together to ward off any potential police advancement, and some pulled bricks up from the road to use as potential projectiles.
A furious Hong Kong politician turned on police, accusing them of being disrespectful as chaos ensues near the parliament.
Charles Mok visited the protest, defending the crowd as "well-meaning citizens" exercising freedom of expression.
"I am worried that they (police) might just use force to remove these people and arrest them all," Mr Mok said. "This is not Hong Kong."
In a heated confrontation with a policeman translated by journalist Naomi Ng, Mr Mok said: "What kind of attitude towards lawmakers is this?"
The officer responded: "It's about mutual respect."
Mr Mok replied: "I'm very respectful. But you are disrespecting lawmakers. What do you think you're doing here? You're beating up Hong Kongers."
Police then warned him to "Be careful. Protecting yourself is what's most important."
Mr Mok pointed his finger and angrily said: "This is the Legislative Council. Do you think you're the boss around here? You keep saying you are wounded? [With police like you], it's game over for Hong Kong."
Volunteers handed out supplies of food, water, umbrellas and masks to fellow marchers. Groups of protesters also formed neat trains to deliver components for barricades. Several people were injured, with ambulances called in.
The demonstrations are the largest since the so-called Umbrella Movement occupied part of the city center for more than two months in 2014. Those gatherings elicited fierce responses from police that included firing tear gas at the mostly student protesters, who held up yellow umbrellas for protection. People came out in force to support them, creating a standoff that lasted 79 days.
Authorities ultimately imprisoned Joshua Wong, a student activist who was the face of the demonstrations, after he was convicted of staging an unlawful rally. He recently was jailed again, this time for contempt of court. Other organisers, including an associate law professor at the University of Hong Kong, were given jail terms.
This week's protests differ from 2014's in important ways, however. The Umbrella Movement called for granting a right - universal suffrage - that Hong Kong's citizens have never had, while opponents believe the extradition law threatens to take away the status as safe haven from Beijing that they have long enjoyed.
Although part of China, the mainland guarantees the former British colony free speech, capitalist markets and English common law under a "one country, two systems'' framework.
Lam, a pro-Beijing leader who's been criticised bitterly by democracy activists, now faces a no-win situation. Passing the law could spark an all-out confrontation with fellow citizens, at least 240,000 of whom turned out in rallies on Sunday. Organisers said they numbered more than one million.
"If we put a halt to this today, the consequences will only be larger, because when this happens again and again, we'd still use the same method to solve it - that when there are lots of resistance, we would give up," Lam said. "Is this beneficial for Hong Kong? We have to think about it seriously."
Backing down could antagonise China's President, Xi Jinping, who's seeking to bring Hong Kong into greater alignment with the mainland. It could also send what the Chinese Government might see as a highly dangerous message to Hong Kong's people: that protest still works.
"It's pretty difficult to see where the Government can go from here," said Tim Summers, a Hong Kong-based senior consulting fellow at the Chatham House think-tank. "They've got themselves in a corner on this one."
While some opponents have exaggerated the law's importance, he said, "It makes people feel insecure and brings out their lack of trust in the central Government and their anxiety about Hong Kong's future."
As the day went on, protests spread from the vicinity of the Legislative Council building, in the city's Admiralty section, and into the financial district, where hundreds of international companies have their local offices. Organisers say they plan to remain in the streets until the government relents, and some participants chanted: "Persist, Hong Kongers! Fight On!''
There also are signs the protest may spread into the economy as a whole. Aviation workers, a teachers' union, student associations and the Confederation of Trade Unions, a pro-democracy labor group, have called for a large-scale strike.
If the bill gets to a vote, it's highly likely to pass: pro-Beijing legislators enjoy a comfortable majority in the legislature, where many of the seats are held by representatives of business and professional groups. Lam has said China has nothing to do with the extradition bill - a claim viewed by protesters with scepticism, particularly as mainland officials have backed her efforts.
More is at stake than the orderly functioning of one of Asia's most-important cities. Hong Kong's independent legal system is the foundation of its distinctive status, a legacy of British rule that has prompted almost 1400 multinationals to set up regional headquarters in the city.
Preserving that system, along with other elements of Hong Kong's autonomy, was at the heart of the 1997 handover agreement between the UK and mainland China.
Hong Kong's government has backed down before in the face of protests, pulling an unpopular national security bill in 2003 and another proposal to require patriotic education in 2012. But authorities have got tougher since the Occupy protests, barring pro-democracy candidates from running for office and banning political parties from advocating Hong Kong's independence. A draft law now under consideration would criminalise disrespect of the Chinese national anthem.
With pro-democracy groups previously in retreat, Lam has "just reinvigorated a dormant movement," said David Zweig, a professor of social science at the Hong Kong University of Science and Technology.
Like many in the city, he's fearful of a true worst-case scenario: an escalation of unrest that tempts China, which maintains a substantial military garrison in Hong Kong, to intervene directly.
"There are certainly people in the crowd who are capable of extreme violence," he said. "If they do that, what's to stop Beijing from saying: We have to go in?"
The vast majority of the protesters, however, appear to be ordinary Hong Kongers: teachers, office workers, retirees and students, many wearied by what they view as a years-long campaign to undermine their city's autonomy. For some of them, this week's demonstrations are being treated as something of a last stand.
"This time the issue is very specific: that we cannot pass the evil law," said Jason Chen, a retired social worker directing pedestrians to the protest outside the Admiralty subway station. "In 2014, it was more general. This is life or death."