Volume 4, Act 14
Yuuto's long-lost love is, of course, dragged into some sort of trouble (since Tokyo is a cesspool of violence and malice in this manga). Now Yuuto gets to save someone other than Kotarou for a change, and we all learn a little lesson about being true to yourself ... or the importance of a firm handshake, or something.
Granted, Yuuto's backstory is a little lame, but seeing him get to angst a little is simply lovely for the Yuuto fans.