Having gotten their fill of an endless summer during their class trip to Hawaii, Yoshin and his pals return to Japan—only to find that it's the middle of winter back home! The sudden change in temperature has our lovebirds catching cold, but when they recover and get back into the swing of things, Christmas is already just around the corner. Of course, spending the holiday season together is nothing but pure joy, especially when Yoshin gets to enjoy another significant event with Nanami—his birthday—even if he has forgotten all about it himself. With a party on Christmas Eve among all their friends and a more intimate affair with just the two of them on Christmas Day, our couple can't get enough merriment and cheer between them!