Related Clues:

• "Once __ a midnight ..."
• Chance ___ (meet accidentally)
• 'Once -- a Mattress'
• Not under
• In the saddle, e.g.
• On the pinnacle
• Story starter, after ''Once''
• ''... ___ a midnight dreary''
• Having surmounted
• Sitting upon
• Word in some British place names
• 'Once -- a time'
• 18 Down follower
• '___ my word!'
• At the occasion of