A good while ago like 2009 there was a series named something like by the orange/apple tree?!?
It was about a well to do brother and sister. They meet a girl at uni who has a more humble background. One night there is a party at the siblings very posh house and the brother kills someone. I think it's the sisters druggy bf. He then dumps humble girl and goes to prison. Sister disappears and turns up with a newborn later on (dead bfs baby) she dumps baby on humble girl and disappears again. Well to do brother turns back up and assumes the baby is humble girls and his. She's besotted with him so they get back to together and she doesn't tell him baby is his niece.
Fast forward 10 years or so humble girl finds out she's pregnant. Their supposed daughter is getting gip in school as someone found out her dad's done time for murder. They live in the same mansion. The girls real mum returns and starts taunting humble girl. Humble girl strangles her.
Sorry for all the humble girl references. Anyone remember this ??