Rin befriends Kouki, a boy she met at the local nursery school, while Daikichi's pulse races a bit when he meets Kouki's beautiful single mother. Later, the modem Daikichi found leads him to his grandfather's last words. And from there, he receives a contact number for Rin's mother, Masako...

At school, Rin is concerned that the disobedient Kouki is getting off track and getting a bad reputation. Meanwhile, when a typhoon hits, Kouki and his mom take shelter with Daikichi and Rin at their house.