While Mamoru and Yuuna are studying, Airi is distracted by a photo album with photos of the childhood friends. Outside Yuuna’s house, Hotaru shows up right before Yamame, and the two get into a fight because they’ve both brought snacks for Mamoru. Tsubaki also comes with food, and they join the three already inside. Still caught up on the album, Airi calls Mamoru a stalker because he’s in all of the photos. Yuuna explains that their fathers were also childhood friends, and so she and Mamoru have been together since they were little. Staring at a photo where he’s holding a plushie of himself and one of Burumaru, Mamoru remembers an event of the past.
Seven years ago, Mamoru was a young boy tasked with protecting Yuuna. When she forgot her textbook, he went home to get it for her. When she was going to be hit in dodge ball, he took a ball in the face. When they were cleaning the principal’s office together, he took the blame for breaking a statue. But being less than devoted than he is now, saving Yuuna each time took its toll until Mamoru finally abandoned her. After sulking on the roof for while, he went to find Yuuna, but she wasn’t in any of her normal spots. He checked for her at her house but instead found her open diary. Yuuna had written the night before that she was going to give him a promised present. Mamoru didn’t remember the promise, but then overheard that Yuuna got kidnapped.
With his own parents nowhere to be found, Mamoru set out with Burumaru. Based on smell, Burumaru led them to a construction zone ands defeated a savage dog. Mamoru discovered their classmate Ami, and she gave him the present that Yuuna had wanted to give him (a Burumaru doll), along with a clue about a red sports car taking her away. By nightfall, Mamoru still hadn’t found the car and was getting more and more frustrated. He realized that it’s his fault and then finally remembered the promise: during a past birthday, she had made a plushie of him, and had promised to give him a Burumaru one next time. Mamoru regained his will to protect Yuuna, and by chance, a red sports car passed by. Mamoru followed it to a warehouse and knocked down the three kidnappers, but one of them smacked him with a rod and turned the tables. Only the appearance of his parents saved him from a beating. They scolded him, and then the entire family took off when the police arrived. Mamoru vowed to always protect Yuuna and see her smile, feelings that have more or less lasted until now.
Between young Yuuna and her friend Ami, there’s just too much cute in this episode. Unfortunately for Mamoru, Yuuna was just as, if not more, dense then as she is now. However, the whole point of the episode is to show that Mamoru went from treating the task of guarding Yuuna as a job to something that he actually wants to do.
I’d personally like to see more Hotaru vs. Yamame because that’s got some good comedic potential. But next week will be about Airi.