That was sweet and you incorporated the requirements well.  I haven't thought of a Night-Blooming Cereus in years.  Once upon a time about 35 years ago, our neighbor set hers out and several neighbors gathered to watch it bloom.  I came home from a date and joined the impromptu party.  all these years later, the boy I went out with married my sister's freind, I don't even remember what we did on that long-ago date, but I have a nice warm memory of several families gathering on a summer saturday night to celebrate the rarely blooming houseplant of our next door neighbor.Thanks for the memory, and thanks for a sweet story about Neville and Lisa. (Gotta love Neviile!)  Makes me want to go write a story about Orla Quirke, now.

Being both a Snape and a Neville fan, I greatly enjoyed reading this. Ecellent use of the prompt