On Mother's Day Koyomi gets into a fight with his sisters and leaves home to find himself in a large playground. While he there Senjogahara arrives to toy with him, showing him her new outfit and telling him how she wants to be "firends". As they continue with their conversations Koyomi notice a young girl who has returned several times to look at a map of the area. He ask if she need help finding where she needs to go but she first refuses his help, then ignores him, and finally get into a full blown fight with Koyomi. The young girl is Mayoi Hachikuji who says she is not only lost she is a 'Lost Snail'.