Marchlands was first shown on ITV on 3 February 2011. It is the first series in the trilogy, and follows a story of three different families living in the same house in Yorkshire in three different time periods - 1968, 1987 and 2010. The three families are linked by the spirit of a young girl who died under mysterious circumstances in 1967. (Wikipedia)

In 1968, Ruth and Paul Bowen live in Marchlands with Paul's parents Robert and Evelyn. Six months earlier, Ruth and Paul's daughter Alice died, apparently in an accidental drowning, and Ruth is determined to find out the truth about what happened to her, believing there is more to Alice's death than she is being led to believe.
In 1987, Helen and Eddie Maynard rent Marchlands and live with their two children. They discover their daughter Amy has what seems to be an imaginary friend called Alice, which they initially try to ignore. After a series of suspiciously paranormal activities, matters become more serious when Amy blames Alice for the death of a kitten, leading to her parents sending Amy for medical tests.
In 2010, Mark Ashburn and his pregnant partner Nisha Parekh move into Marchlands and find a photo of a young girl, who the viewers now know to be Alice. Nisha becomes suspicious that Mark has not told her the whole truth about why they have moved there. An elderly Ruth, who never came to terms with the death of her child and remains determined to find out what happened, returns to Marchlands when Mark employs her as a housekeeper and childminder after Nisha breaks her ankle when falling from a step-ladder. (Wikipedia)

In 1968 Paul and Ruth reconcile though,after Brian has boasted of sleeping with Ruth,Paul punches him. Robert tells his son he thinks he should take Ruth out of the area to make a fresh start but she is still convinced that there was more to her daughter's drowning than the official verdict,that she wandered off whilst out walking with her grandfather. In 1987,as Scott begins to have epileptic fits,Eddie brings Father Boyle in to exorcise Amy's room,though this leads to a row between Helen and Eddie,causing Amy to run away into the woods, where she is saved from falling into the lake by Olive.(IMDB)

Trailer: https://www.youtube.com/watch?v=Z2iiO92AKYM