Donna and the Doctor invite themselves to a garden party in England in 1926. They are delighted when they find out that Agatha Christie is a guest as well. The festivities are soon disturbed by a murder in the library but who is the killer? It has to bee someone from the party guests and so the Doctor and Donna help Agatha to investigate. After a while, it looks more and more like they are all in one of Agatha's books and there is even someone who tries to kill the Doctor but he's not so easy to kill and survives the attack. Everything seems to be linked to one locked room in the manor and soon Donna faces a giant wasp that tries to kill her. Will they be able to solve the mystery and save the people in the house?
I think this is a great episode, not only because I like Agatha Christie but also because it is really funny despite the murders. Some events from the past are mentioned as well, like when Donna asks if Charles Dickens was surrounded by ghosts on Christmas. We all know that this happened before. I really love the scene between Donna and the Doctor in the kitchen when he tries to get the poison out of his body. It's just brilliantly played and it was definitely a shock when for the Doctor when Donna kissed him. I like the way they used Agatha's lost ten days in this episode and that not everything is fictional in the episodes. The giant wasp was a bit scary especially when you didn't know what killed all the people. All in all, a great stand-alone episode.