The Black-Eyed Maiden

John and Sherlock are on a case which requires help only the Winchesters can provide. Things get complicated when Sam and John go missing and the only clue they can gather is a blue Police Box parked in the corner of Baker Street. Will Sam and John return in time? Or will the case of The Black-Eyed Maiden forever remain a mystery? ((Superwholock fic, please review! :D ))