Pita-Ten Vol 6

From the Tokyopop edition

In a revealing adventure of historic proportions, Kotarou tries to discover the truth behind his relation to Misha and Shia. The mystery, memories and mayhem of the past are the keys to unlocking the forgotten promises that will finally bring Kotarou, Misha and Shia together for a happy future ... or will they?

Source: Anime News Network Encyclopedia