Kouta and Rurumo’s romance was always simple and sweet, based on mutual kindness and fondness, with little in the way of serious drama getting in the way of their happiness. The only kink was Ruru’s training; to complete it Kouta would have to spend all of his magical tickets, whereupon his life would end. But that’s just not how things ended up working out.
The tickets, in the end, kinda fell by the wayside, along with the vast majority of magical stuff; something I really didn’t mind at all. As much as I enjoy magical shows, I was more invested in the human relationship being cultivated than any magical bureaucratic nonsense going on in the background. The show seems to understand this as well, which is what makes Rurumo’s explanation of what the heck happened for most of the episode a pleasant surprise.
It all starts as New Year’s nears, and Kouta seeks something to present to Ruru as a token of his affection, and finds it in a rather expensive yukata rental he must work a part-time job to afford. First of all, kudos to Kouta: he’s become a fine young man, and his perverse tendencies have become almost as peripheral as the magic tickets. He can’t use those to make money, because it wouldn’t be a surprise.
He gathers the necessary funds,then falls asleep under the kotatsu, and the morning of New Year’s turns out to be the titular “Day Without Rurumo.” Kouta has no direct memories of Ruru, nor does his family or friends, though there are little clues here and there that tweak Kouta’s memory, though not long enough to fully remember her. This is a little alarming at first, but something about the way it was unfolding told us it would turn out alright in the end.
That turns out to be the case, as as soon as the clock strikes twelve—maybe a second or two before hand—Kouta remembers Rurumo, just as she’s passing him by in the yukata he bought her. New Year’s Eve happened to be the day of her “evaluation”, which meant everyone she knew had their memories temporarily wiped to avoid interference. What seemed like a huge dilemma turned out to be the magical equivalent of an annual review.
When he hangs his wish to the future at the shrine, Kouta apologizes to Ruru for not being of any help whatsoever in her training, but the fact is, neither of them want the training to end, not just because it would kill him, but because they like being around each other and don’t want that to end. Like I said: simple and sweet.