Operation: Her First Christmas (One-Shot)

{This is an entry for a competition.}
It's surprising how two people with so many issues can find love. Nami Era has never celebrated Christmas, Luke Kings has never gotten over someone really important to him. But how, when Luke has an idea to plan a Christmas party for Nami, do they find out the meaning of Christmas? As deaths, tragedies, and some party planning all rushes in at once, will the operation be a success? Or will more people just be struck by sadness?