Castle Vertalia

When Olive Dyer and her twin brother Owen Dyer go on their family vacation to see their grandparents (the king and queen of Vertalia) they find that someone is trying to murder their grandparents and wipe out the whole Dyer family. Will Olive and Owen find the killer before it's too late? Or will the murder succeed and become the new king/queen of Vertalia? Find out in Medieval Mysteries!