Wymering Manor in Portsmouth, Hants, is said to be haunted by a choir of nuns who scuttle across hallways as well as a host of unseen hands which reach out and touch passers by.
The property, thought to be the oldest house in Portsmouth having been mentioned in the 1086 Doomsday book, was placed on sale at an auction with a reserve price of £375,000 last year but failed to sell.
The group will attempt to restore the house to its former glory, estimated at a total cost of more than £500,000, before opening it as a tourist attraction.
The spirits of whispering children and Sir Roderick of Porchester, who was murdered outside the manor in the middle ages, are said to be among the ghosts haunting the property.
Ghost-hunters have reported the sudden drops in temperature and other strange apparitions that go on inside the building.
David Scanla, who used to live in the house, said he hadn't had any problems with ghosts but calimed he had seen them.
Portsmouth City Council bought the property in the 1960's and leased it to the Youth Hostel Association until 2006.
Jeremy Lamb, a chartered surveyor who tried to sell the property in 2010, said: "It's certainly a unique house.
"Although they patrol it on a 24-hour basis because it attracts lots of people who are intrigued by its levels of paranormal activity, they refuse to work alone there at night."