From the December House Blog:
We want you to write three pieces of Flash Fiction on the theme "The 7 Deadly Sins" and then upload it to Wattpad, tagged "FlashFictionFest", by the 19th of September.
After that date the December House Team will read every entry and the writer judged to have the best three pieces will have them included in the online event in November and published in the e-book, we may even ask you write some more to go with them! But that's not all, if you're the winner you'll also get the chance to work with our editor on a novel with the intention being to prepare it for publication by December House.
December House sponsored a similar contest last year. For more details, see the contest announcement here.