Pita-Ten Vol 7

From the Tokyopop edition

Grim times await Kotarou, Shia, and Misha as Katorou pays his final respects to his dearly departed grandfather. In this tale of transcendent love, the dark secret that Misha has been harboring–the very reason for coming to Earth–is finally revealed. Unfortunately, her friendship with Kotarou might not be strong enough to withstand the shocking truth!

Source: Anime News Network Encyclopedia