Almost a year after they started dating, Junichi and Ai are reflecting over their time together at the beach. With Junichi studying at a cram school and Ai tending to her responsibilities as captain of the swim team and at home, they are spending less time together, though they are looking forward to their date on Christmas Eve. One morning, after Junichi studies too late, Ai goes to wake up Junichi and walks with him to school as they pass by Ai's teammates. After spending some time at the library studying, Junichi decides to visit Ai, only for the swim team, which includes Miya who recently joined, to reprimand him of his actions. Soon after, Junichi finds himself sleeping at the infirmary after another late night study session. Ai decides to visit him as Junichi asks her to let him sleep on her belly while singing him a lullaby. As Christmas Eve approaches, Junichi runs into a problem when he accidentally marks the answers in the wrong spots during a practice test at cram school and thus has to take a training camp which starts on the 23rd of December, canceling their plans for their date. Ai reassures him that she will be fine but soon becomes depressed as they are barely spending time due to their responsibilities. Some time before Junichi leaves, Ai decides to give Junichi a present to help encourage him during his training camp. However, Miya tells her that because of his bad score, the cram school took him away earlier than projected, leaving Ai to wander the festive streets alone without her boyfriend.