The Wicked Widow

Since their father Lord Shenley passed away, beautiful young Kyle Shenley and her little brother Terry have no-one to care for them except their despised stepmother Sybil, who has already taken a lover and is plotting to get her hands on the children's inheritance. When Kyla overhears her plans to ensure young Terry has a "fatal accident" and to drug Kyla and hand her over to a ghastly old man called Lord Frome to face a life of debauchery, she sees no alternative but for them both to flee. Heading for Lilliecote Castle and their beloved Nanny, they're accosted by a highwayman on the road but he turns out to be a particularly nice "gentleman of the road" who demands only one of their sandwiches - and even offers his protection should they find themselves in dire straits.
When they arrive at the Castle, Nanny suggests that the Master, the Earl of Granston should not be aware of their identities in case their wicked stepmother comes there seeking them and, passing off Kyla as a new Governess to the Earl's young niece, Nanny shows them how to hide in the Castle's ancient secret passages and priests' holes. But as the handsome and authoritative Earl takes them under his wing, he suspects there's more to Kyla than meets the eye - and eventually it is he, together with their highwayman friend, who defeats the wicked widow and her gang of evil accomplices in a terrifying battle in which the Earl wins Kyla's heart.