A woman who injured her ankle while walking on Winter Hill was rescued along with her brother.
The pair were walking at the beauty spot on Tuesday night before they were separated as the mist thickened.
Bolton Mountain Rescue teams, along with Lancashire Police, were called just before 9.40pm on Tuesday (August 27).
They quickly found the 15-year-old boy. The 22-year-old woman was discovered in a boggy spot.
She had a serious ankle injury and was unable to walk.
The woman was carried off the hill on a stretcher, while a police helicopter provided light from above.
A Mountain Rescue Land Rover took her to hospital, where she remains.
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Bolton Mountain Rescue posted details of the incident on Facebook.
"A quick response from Police officers and Mountain Rescue volunteers led to the male being located and taken to safety," the post read.
"The female was soon located in a particularly boggy spot on the moor by MRT personnel searching on foot, with assistance from the National Air Service HQ helicopter from City Airport Manchester above. She was also joined on scene by family members.
"The female had sustained a serious ankle injury, was cold, wet and unable to walk. She was protected from the elements whilst her injuries were treated by team members.
"Once stabilised she was carried off the hill on a stretcher to team vehicles waiting on Coal Pit Road, and then conveyed in one of our Land Rovers for further treatment at Royal Bolton Hospital.
"Throughout the incident the police helicopter remained overhead to provide lighting.
"In total 27 team members were involved in this incident, working alongside many officers at Lancashire Constabulary and the NPAS Helicopter air crew.
"We wish the female involved a swift and full recovery from her injuries."
