Heart Strings summary: Due to unexpected events, Sakaki ends up being Yuki's "customer" and he's touched by Sakaki's words... but after discovering that a sweet fleeting kiss was just a game, what will Yuki do? Never fear; keep strong and keep believing! A love battle showdown between a yakuza and his wife! (Includes unreleased pages.) Loosely connected to 'Twin's Labyrinth'. The final chapter "Love go-round" also invovles Rin and Ayumu from 'Twin's Labyrinth'.