The grainy CCTV footage shows a couple dressed for a day wandering Taiwan's so-called Mysterious Valley Trail.
Sim Hwee Kok is wearing hiking boots and cargo shorts, while his wife Neo Siew Choo has a cross-body bag slung over her shoulder.
The security video taken from a sightseeing bus on April 3 suggests the Singaporean-Australian couple got off for a hike through Taroko National Park in eastern Taiwan.
Home to the Shakadang Trail — known to some as Mysterious Valley Trail — it's a place of unimaginable natural beauty.
Hikers squeeze themselves along imposing marble cliffs to marvel at the clear blue river below.
But 38 minutes after Sim Hwee Kok and Neo Siew Choo got off the bus, another, harsher force of nature took hold of Taiwan.
The island's east coast sits on top of two converging tectonic plates, and at 7:58am these two gargantuan slabs of rock slid against each other.
It produced the largest quake to strike Taiwan in a quarter of a century, leaving 13 people dead and more than 1,100 injured.
Built to withstand the angry rumblings of the tectonic plates below, Taipei fared relatively well through the seismic shock.
But out in the wilderness, chaos reigned.
Massive landslides of boulders and dirt toppled down Taroko National Park's famously rugged mountain terrain.
The disaster trapped hundreds of people inside the park, with roads and tunnels sealed off by huge piles of rubble.
Rescuers are now in a race against time to free those stranded in the park.
But two hikers, Sim Hwee Kok and Neo Siew Choo, appear to have vanished without a trace.
The desperate search for those missing in the quake
A 10-storey red brick building left leaning precariously after last week's earthquake has become a global symbol of the damage wrought by the tremor.
The Ministry of Agriculture said Taiwan has recorded 779 aftershocks, including two above magnitude-6, in the period between when the quake first struck and April 9.
The partially collapsed tower loomed large over a street in Hualien City, which is widely considered to be the epicentre of the quake.
But it was the image of men and women dressed in yellow and red jumpsuits along with their canine coworkers that came to define the aftermath of the tragedy and the desperate search for survivors.
Roger the Labrador made headlines as part of the city-wide endeavour after locating the body of the quake's 13th victim.
The dog detective had failed in his first career as a drug sniffer due to his playful temperament but helped to lift the mood of a nation as he tore apart a soft toy at a press conference on the quake this week.
When the quake struck during morning rush hour, it sent schoolchildren, commuters and families scrambling for shelter.
Others who were travelling at the time weren't so lucky and soon found themselves trapped within Hualien's road tunnels.
A group of about 50 hotel employees from Silks Place Taroko Hotel were making their way through one of these routes on four minibuses when the quake hit.
An employee recounted anxiously waiting for help to arrive after giant rocks had crashed down and blocked their entry and exit points.
"We didn't have any food, but some of our employees had brought their own breakfast, and we had some bottled water in the bus," David Chen told The Associated Press.
"I handed it out and told them to be sparing, you can't die from hunger, but you can die from thirst."
They were eventually freed from the blocked passage thanks to the help of workers using heavy machinery.
Taiwan's rescue efforts initially focused on people trapped under rubble and collapsed buildings in the city.
But the search area was soon broadened out to include surrounding regions and popular tourist hiking spots, where earthquakes triggered landslides.
At first, authorities hoped to zero in on missing travellers by using phone signals but were largely cut off from accessing the area due to road blockages.
The bodies of five hikers who were on the Shakadang trail were recovered on April 10, but Sim Hwee Kok and Neo Siew Choo are still unaccounted-for.
With little more than the CCTV footage of their last moments to go off, rescue teams have pieced together a picture of where the couple might be trapped.
What do we know about the place they were last seen?
Taiwan is situated in one of the most seismically active regions in the world. In Eastern Taiwan, the earth is lifting upwards as the Philippine Sea plate and the Eurasian plate come together.
While this region has a history of strong earthquakes, the most recent rupture is believed to have occurred on what's called a "reverse fault".
"This is where the quake lifts up one side of the Earth's crust relative to the other," Dee Ninis wrote in The Conversation.
The United States Geological Survey said the Philippine Sea plate was moving north-west and "subducting below the Eurasian plate".
The April 3 rupture was the strongest Taiwan has felt in 25 years — a period of time that becomes insignificant when considering the geological history of the region.
[Epicentre map]For millions of years, seismic activity has pushed marble and rock upwards while the Liwu River has carved a path between them. What can be seen today are the steep walls of the Taroko Gorge — a location considered one of the main attractions inside the national park.
But the seismic activity that created the picturesque landscape tourists come to see also puts them at risk of disaster.
The bus to Taroko National Park is believed to have dropped Sim Hwee Kok and Neo Siew Choo off at the Shakadang — or Mysterious Valley — Trail.
The time stamp on the vision of them arriving puts them on the ground at 7:20am.
A popular option for tourists is the Taiwan Tourist Shuttle Service, which stops just near the Shakadang trail head about 1.3 kilometres inside the national park.
The track is a flat walk considered appropriate for even novice hikers, but it's not a loop circuit.
Hikers travel 4.1 kilometres one way before turning around and heading back and it's estimated the full return trip would take 3 to 4 hours.
A video taken by a German tourist and shared with the Guardian appears to have shed further light on their whereabouts, showing the couple beginning their hike on the Shakadang trail a mere 25 minutes before the quake hit.
It's believed that for those 25 minutes, Sim Hwee Kok and Neo Siew Choo were making their way along the Mysterious Valley Track, moving further into Taroko National Park.
The 'golden period' has passed
Rescuers refer to the 72 hours after a natural disaster as "the golden period".
If someone is trapped with limited access to food, water and medical attention, their best chance of survival is being found within three days.
It has now been 10 days since the quake triggered landslides in the Mysterious Valley Track.
Search and rescue personnel believe that Sim Hwee Kok and Neo Siew Choo were last seen near a large water pipe about 1.8km from the trail's entrance.
Local media reported six rescue workers and three dogs were dispatched to search the area on April 10, but no trace of the pair was discovered.
Australia's Department of Foreign Affairs is providing consular assistance to the couple's families.
"The Australian office in Taipei is liaising with local authorities, whose search for the missing Australians is ongoing," a spokesperson said in a statement to the ABC.
Search operations have been hindered by aftershocks, rockfalls and bad weather, which has forced excavation attempts to be delayed or called off.
"It’s like the entire mountains of Taroko collapsed, trapping so many people inside the mountain," firefighter Wen Zong Hao told Al Jazeera.
"This is very different and much more challenging than an ordinary urban search and rescue mission."
While the search continues for the missing Australian hikers, there has been some good news for rescuers digging in the dirt and rubble.
A family of five who were hiking along the Shakadang Trails when the quake hit were found alive by members of Taiwan’s Red Cross after four days.
