In the Chateau, three people lived. These were the owner, the owner's daughter, and their butler. The owner was a previously renowned scientist, who had been making large strides in the fields of Pokemon research. However, when his wife died (The child's mother, obviously), the scientist, without telling his child or butler, refrigerated her dead body underneath the (now glaring) statue in the main room.
Now, the scientist devoted his time to his research, which was now focusing on creating a living Pokemon from scratch. He believed that if he could do this, he could one day revive his dead wife, who he cannot live without. The butler, who had been great friends with him, became greedy and believed that he could do so much more with the scientist's money than he was. He was second in line in the will for the fortune of the scientist, after the scientist's daughter. So he decided to poison both to acquire the house himself.
However, the girl found out about his plan. She tried to warn her dad, but he was too devoted to his research to listen. She decided to hide the antidote the servant had at the last minute, in the trash can, so she could save her father later. She used the substitute so that only her copy would be poisoned.
The butler had to eat some of the Old Gateau with the other two, since he ate with them avery night. The scientist considered him a friend, more than anything. The scientist, who was on the verge of a breakthrough, took some with him into his room so he could continue working. The butler died because he could not find the antidote. When the scientist found out, he went into denial, not believing his daughter about the evil butler. He locked himself in his room for the next week, working non-stop to complete his experiments. The Butler's body was left lying in the kitchen. The police were not called. The girl tried desperately to get in, but he always shouted at her to get away. He ate nothing and drank very little.
Finally, by electrifying a blob of plasma, he finally created Rotom. Then he died. Some say it was from exhaustion, other from a heart attack or stroke. Some others even say Rotom killed him. Anyway, the girl then lost the will to live when she managed to get in the room only to find her father dead. She was found dead next to him, still clutching his shirt.
A couple weeks later, the brother of the girl's mother, Mr. Backlot came by to visit his niece. He found the three dead bodies. He had a mimic of the statue that had been made as a "memorial" to the mother (he didn't know her body was under the original). He made the trophy garden as a memorial to his niece, who loved all the Pokemon that are commonly found there. The Rotom took up residence on the T.V. and Gengars were drawn to the room with the painting, where they play tricks on visitors. The glaring statue is the mother's soul, seeking rest. The girl and the butler still show up sometimes at the mansion as ghosts. The gateau was left sitting in the lab all these years, where the poison eventually became dormant and unharmful.