In secret, groups of demonstrators have been devising a plan to stop the government bringing in a controversial law allowing extraditions to countries including mainland China.
On Sunday, hundreds of thousands of people took part in a peaceful protest but a small number turned to violence.
Among them were students, Peter and Ivan (not their real names) who agreed to speak to Sky News anonymously.
They're now planning their next move ahead of a second reading of the bill on Wednesday.
"Our protest will only be more violent and violent until the government responds to the requests of Hong Kong's people," Ivan said.
"We don't want to hurt anyone, but if the police do some violent actions on us we cannot wait for them to hit us. We have to fight back to defend ourselves."
Young mother Kitty Hung brought her three-year-old to Sunday's demonstration.
She's opposed to the violence but is also against the new law which she believes will put her daughter's future at stake.
She told Sky News: "I want her to grow up in a place she can live without fear. I have some family in China and they cannot publicly speak out about government or political issues. I don't want that for my girl."
While the extradition bill has been the catalyst for demonstrators including Kitty, their fight is about something so much bigger.
Many see this week as the last chance to protect fundamental freedoms they enjoy in Hong Kong - freedoms they would not get in mainland China.
Despite this opposition, the government isn't backing down and says Wednesday's debate will go ahead.
Ronny Tong, a member of Hong Kong's Executive Council, is adamant there's no reason to worry.
He says safeguards are in place to defend human rights.
He said: "This bill deals with crimes committed abroad, not crimes committed by Hong Kong people but crimes committed by anyone abroad. If you don't send your children abroad to commit crimes, why should you worry?"
Despite government reassurances, though, suspicions of Beijing run deep.
In a street, I spot magazines gossiping about China's president but quickly the shopkeeper covers them up.
In recent years, a number of Hong Kong's booksellers have disappeared or been detained by the Chinese.
Among them is Lam Wing Kee, who was imprisoned by mainland security agents in 2015 after publishing works critical of the Communist Party leadership.
He's now fled to Taiwan from Hong Kong, fearing he would face extradition to China if the law went ahead.
"If the bill is passed, it's a death sentence for Hong Kong," he warned. "Hong Kong will lose its free status - the personal safety of every citizen will be in doubt."
Thousands of extra police have been brought in ahead of Wednesday's debate.
At the train station they search people as they come through the barriers.
Hong Kong is now a city on edge.