The twelfth volume of the Sora no Otoshimono manga was first released on June 4th, 2011 by the Kadokawa Shoten Publishing Corporation. This volume includes the return of Angeloid Chaos and Angeloid Hiyori to the main plot (although Hiyori only makes several brief appearances) while Tomoki gets carried away with his over-the-top perverted antics. It also introduces us to Tomoki's parents, who have been gone touring the world ever since his tenth birthday roughly six years ago.
Chapter Forty Seven: The Road Home
Chapter Forty Eight: Stray Dogs
Chapter Forty Nine: Sakurai
Chapter Fifty: Measurement