December, 1922. Ruby Vaughn expects nothing exciting from a quiet pre-Christmas visit to Oxford with her elderly employer, Mr Owen. Far from the strange and sometimes dangerous books that pass through their shop and with Mr Owen due to attend meetings of the antiquarian society, Ruby hopes for a peaceful week. But when the body of disgraced scholar Julius Harker is discovered among his exhibition of Egyptian antiquities, panic spreads throughout the city's cobbled streets. Drawn reluctantly into the mystery by an old friend, Ruby soon realises Oxford is hiding dangerous secrets - especially when Ruan Kivell, the enigmatic folk healer she met in Cornwall, unexpectedly reappears.