I do not own Doctor Who or Once Upon a Time. Only this story. Enjoy! :)

Chapter 1: The Poison Fairy

(*FLASHBACK*)

Missy sat in her office at the 3W Institute feeling frustrated. It was taking a very long time for the various aspects of her plan to fall into place. She needed a source of powerful magic. She tried to take the Blue Diamond, one of the most powerful objects in the entire universe, but Rumplestiltskin sent it to a parallel world where even a Time Lords can't go. She tried on numerous occasions to take the Eye of Life, one of the three magic eyes of the mystic Fates. It had enough power to do what she wanted, but she could never get it. The other two eyes were on different worlds, and Missy didn't know which ones. She had to find a new source of powerful magic. It took some time, but she eventually discovered a powerful object hidden in the mountains of Arendelle. With it, she could absolutely do what she needed. After that, it was all a matter of getting the Dark One on her side, but that was a problem for another day. Missy pressed the button on the intercom system on her desk and spoke into it.

"Ria." Missy said. "I need to see you."

Ria was one of Missy's special employees. She was born in the Enchanted Forest as a fairy. However, she had the uncommon talents of dark magic. She became known as the Poison Fairy. The Blue Fairy saw her as evil and kicked her out of the fairy home. So, Ria trained in dark magic under Cora, the Queen of Hearts. Ria then went to fight the Blue Fairy and lost. Eventually, she went to work for the Evil Queen. Later, Regina crushed Ria's heart after she failed to kill Snow White and steal the Doctor's TARDIS. When Ria died, she was brought here to 3W. Instead of having her body converted into a Cyberman, Missy saw it as more beneficial to have a dark magic fairy at her side. Instead of being reborn as a Cyberman, she would exist like a zombie. However, she was still powerful and dangerous and could be killed again, which would be permanent. Soon, Ria opened the door and walked into the office. She was tall and had pale skin. Her long hair, dress, and wings were all dark black. She stood in front of Missy's desk.

"What do you need?" Ria asked.

"I need you to do something for me." Missy said. "There's a powerful magical object hidden in the mountains of Arendelle. I need you to find it and take it."

"Of course my mistress." Ria said. "What object am I looking for?"

"The Sorcerer's Hat." Missy said. "However, you must be careful. It's very likely that you'll run into the Snow Queen."