Possible Clues:

• 'It is a riddle, wrapped in a mystery, inside an enigma; but perhaps there is ___': Churchill
• Answer to the riddle 'What force or strength cannot get through / I, with gentle touch, can do'
• Play ___ role
• Charlie Chan mystery 'The House Without ___'
• Solution to the classic riddle 'What force or strength cannot get through, / I, with gentle touch, can do'
• Play __ role in
• __ to the city
• 'The House Without ___' (first Charlie Chan mystery)
• Caps Lock neighbor
• "Take --- and lock her up, my fair..."