As a final-year Law student, Gilbert Hastings takes a holiday job with Lucille Dellow to renovate the Old Stone House in Arbor Valley. The owner of the Old Stone House, Elsie Leggat has moved into a rest home and has been persuaded to sell her house by a corrupt Nadine Norton. Nadine has a hidden motive for listing the old lady's house. The Old Stone House produces a surprise that results in a house fire and Gilbert being charged with murder.. Gilbert does not realise that both he and Lucille are in danger from a hidden killer.