Tazuna and his new friend Koyori have a problem: If Tazuna lets go of Koyori's hand, she'll die! Can he take her home with him and explain to his parents why he now has to live with a girl? And how's he going to take a bath with her!?

Tazuna meets Chizuru and Hayate, the pair who's car he fixed on the day he met Koyori. They're workers for a major food corporation in the area, and they offer to treat him and Koyori to dinner as a thank you. But after the meal, they reveal that they're actually Hand Shakers themselves!

Tazuna and Koyori meet their next opponent: Kodama, a powerful idol singer who has defeated many other Hand Shakers. She and her producer are their toughest opponent yet, and together, they overwhelm Single Gear. Tazuna barely escapes into the water below a nearby bridge...

Tazuna and Koyori battle Awaza Kodama a second time, and she's just as powerful as the first. Tazuna, and Single Gear, cannot hope to defeat her. Their only choice is to rely on Koyori's unseen strength.