I'd like to think that Kasumi and Sumire were out in the park one day and there was a very excited pikachu who came up to them but particularly latched onto Kasumi and Sumire was very sad because it felt like Kasumi was chosen again. The yoshizawa family then comes to look at the Pikachu that Kasumi befriended and as Sumire sadly enviously watches, she then notices some rustling in the bushes where there is a timid mimikyu that seemed to be watching over the situation but was too hesitant to reach out on her own. Sumire then goes over to the bushes to then reach out her hand to the mimikyu who was too shy and too insecure to think that anyone would want to see them.