Set after "We Regret to Inform You" :D Pinkie Pie becomes a mother of six children, not including Pound and Pumpkin Pie-'cake'. Pinkie and Cheese then marry and have kids. The Twins now have to deal with sextuplet additions, making a huge family! :)
Death can be a scary thing, and when the Reaper comes for Pinkie Pie she just isn't ready to go. Fortunately being the bearer of Laughter has it's perks. Death will let her have one last day any day she wishes, to spend time with anypony she wishes.
Set a few years into the future, six year old Pound and Pumpkin have a lot of growing up to do. They fight and make up, make mistakes and learn lessons, and love and protect each other as much as they get on each other's nerves.