Once Upon a Time Machine 1-4: A Mermaid, A Rose, and A War

Peter Pan has sent Ariel to a parallel world to retrieve a powerful and dangerous object for him. However, this world is at war with the Cybermen. Ariel needs the help of Rose Tyler and the human Doctor in order to make it back to her own universe alive. She must also discover what truly happened on Neverland long ago between the Doctor, Rose, and Pan and why Pan wants Rose dead