Complex sentence: They move to a remote mountain home which Karen has inherited from the family of her late husband; however, she is unaware that the home is situated near an old mine, the site of an early 20th century tragedy in which many children were buried alive.
Split into simpler sentences: They move to a remote mountain home which Karen has inherited from the family of her late husband. However, she is unaware that the home is situated near an old mine, the site of an early 20th century tragedy in which many children were buried alive.