Late this Wednesday, Richard Amadi-Emine plans to leave his home - a cramped, windowless 13th-floor room off a corridor decorated with 'Warning, rat poison laid here' posters - and head for St Joseph's Catholic Church on Garden Road.
Marking Christmas is important for the 33-year-old Nigerian, who looks forward to celebrating midnight mass in Hong Kong.
One of many West Africans staying at Chungking Mansions in Tsim Sha Tsui, he buys bundles of cheap clothes to sell at a modest profit back home.
Several freight companies have offices on the ground and first floors of the mansions. Last week the dingy corridors were clogged with traders ramming clothes into cardboard boxes and sealing them with masking tape.
'On Christmas Day I'm going to try eating something Chinese,' Mr Amadi-Emine said.
'I've never eaten snake so I think I'm going to try it, and we're going to get together in somebody's room.
'Christmas in Nigeria is something else, but I can't get on a flight because it's fully booked,' said the trader, who visits Hong Kong two or three times a year, along with trips to Bombay, Dhaka and Seoul.
'The whole family would be around, and we're awake until the following morning, with a lot of drinks.
'Right after Christmas, I'm going to go home.' Mr Amadi-Emine and his fellow West African Christians may celebrate Christmas, but many residents in the mansions are not planning to join them.
Locals, South Asians and African Muslims will be Christmas bystanders - either too busy to party, or choosing to wait for their own religious festivals to come around before celebrating.
Still, there are a few signs around the mansions that the festive season has arrived. Almost unnoticed by the scurrying crowd, a foil banner reading 'Merry Christmas and Happy New Year' flutters in the chill December breeze at the entrance on Nathan Road.
Occasional backpackers dodge fake-watch touts beneath it. One jewellery shop's window display includes a token cardboard cut-out Santa, while a nearby curry house has a touch of tinsel.
Each of the mansions' five blocks has 17 floors, with 900-odd apartments, many converted into cheap guesthouses, narrow workshops, restaurants and souvenir shops. On the higher floors, sunlight seldom penetrates and neon strip-lights blur together night and day.
The Chos run the 13th-floor New Washington Guesthouse where Mr Amadi-Emine stays.
As her husband showed some new arrivals to their rooms, Ms Cho explained they would be too busy to mark Christmas.
'We have to do everything here and if guests come, we have to be around,' she says, squeezing against the wall to let residents get past her in the narrow corridor.
'We have to clean and fix things. There's always so much to do.' Ms Cho arrived from Shanghai four years ago to join her husband. Since there was little emphasis on Christmas on the mainland, she said, it was not important for her to take part.
Three floors below, in the glossily painted nerve-centre of their clothing, stationery, electronics and leather-trading empire, Arif Hossain and his friends do not intend to celebrate Christmas either.
'We're Muslims, so we're going to wait for Eid al-Fitr and Eid al-Adha,' Mr Hossain says, strolling down the dank corridor from the flat he lives in to the neighbouring one that serves as his office. He also rents the two apartments opposite on the 10th floor.
Mr Hossain, a Bangladeshi, has lived in Hong Kong for more than eight years.
'On those days,' he said, explaining the practice back home, 'we buy two or three cows, cut them up and give them to the poor people. The rest of it we'll save for friends and family.' Eid al-Fitr, a feast to mark the end of the month of Ramadan, when Muslims fast from dawn until dusk each day, will likely be held on January 29, according to Nasser el-Morshidy, Da'wah or teacher at Masjid Ammar, a mosque in Wan Chai.
The festival begins with the sighting of the new moon.
Eid al-Adha is at the end of the Hajj, the pilgrimage to the holy city of Mecca that all Muslims are supposed to make at least once in their lives. It will be at the beginning of May next year.
Both festivals, Mr Nasser says, are times for family gatherings and seeing old friends.
For Hindus such as Bob Kripalani, general manager of a first-floor electronics store that measures less than 400 square feet, the major holiday of the year has already passed. Diwali - the Festival of Lights - took place in late October.
But Mr Kripalani says he plans to join in the celebrations for Christmas, New Year and Chinese New Year as well.
Diwali is a five-day celebration. During this time, he says, women and men splash out on new gold jewellery; pray to Laksmi, the goddess of wealth; light candles; exchange fruits and sweets; fly kites and visit family and friends.
In Hong Kong, where the 48-year-old father of three has lived for 28 years, Mr Kripalani says the celebration has been scaled down to three days.
Although December 25 will be a working day for Mr Kripalani, he and his family will likely join the throngs wandering the streets and eat out after closing his shop.
Thursday will also see the 11 wizened men at the Hang On Tailors workshop on the fifth floor of B block bent over their antique sewing machines as usual.
'This is a busy time for us,' said owner Danny Chow Shiu-kau, as his employees stitched half-finished jackets and trousers, most peering at their intricate work through thick glasses.
Overseas customers have ordered suits as Christmas gifts, or for the New Year, Mr Chow says.
'We've seen about 20 to 30 per cent more orders since November,' he says.
For Mr Chow, 50, Christmas was an event to be celebrated with his wife and four children when they were younger. Now in their 20s, his children prefer to spend the holiday with their friends.
'We used to take the kids to see the Christmas lights, walk along the [Tsim Sha Tsui waterfront] promenade or maybe go for yum cha,' Mr Chow recalls.
'Now, it's just another work day.' Chungking Mansions' postman Wong Kam-chi has witnessed each day's events for four years and says Christmas for him, like for most residents and shopkeepers, will pass without much pause for thought.
'One Indian restaurant had a full banquet, lots of food prepared a few weeks ago.
'It was their own festive celebration. But you won't find much going on around here at Christmas,' says the single man in his 30s, whose route includes the neighbouring Holiday Inn Golden Mile.
Watching a football game and eating out with friends is the extent of his plans for the public holiday.
Refusing to have his enthusiasm for Christmas dampened, Dike Lawrence says he still prefers to spend it in his native Nigeria.
Chatting on the grubby landing outside his seventh-floor guesthouse, the 30-year-old Christian says this year will be the second time he has spent the festive season in Hong Kong.
Back home, Mr Lawrence would typically take a bumpy seven-hour bus journey with his wife from their house in Lagos, Nigeria's largest city, to his ancestral village in Imo province in the east of the country. There they would celebrate with his friends and relatives.
'I might try to call my family in Nigeria,' he says.
This time he plans to spend much of Christmas Day at the evangelical Revival Christian Church in Kwai Fong.
'Someone took me there when I first came to Hong Kong,' says Mr Lawrence, another garment trader.
'I'm going to be there on Christmas Day from three o'clock in the afternoon until late at night.'