RCMP say when the men failed to return from a fishing trip, their friends and family alerted authorities, though no one knew exactly where they'd gone.
Mounties say a conservation officer who joined the search found the men's truck parked at Khartoum Lake, where he heard someone calling for help.
They say he drove to a nearby fish hatchery and enlisted the help of staff who returned to the lake with him and discovered a man who'd managed to swim to shore but couldn't hike out because of the rugged terrain.
RCMP say the hypothermic man had spent the night sitting on the shore and was taken to hospital for treatment.
But police say his 44-year-old friend, who was not a strong swimmer, drowned in the frigid water and that his body was discovered two days later.