Arizona wants to throw DeLuca a surprise birthday party, but when it comes to planning, she realizes that she doesn't know everything about him. So she asks the one person who would know him the most - Carina

Arizona does not like to be ghosted. The opposite, on the other hand, turns out to be great fun! Well, at least till things get complicated. Which they do - of course... They always do. (Basically the complete Arizona & Carina story, or at least my take on it, with extended and deleted scenes from ep. 14x01 and beyond - rated M for obvious reasons)