Attack on Titan: Before the Fall Vol 17

From the Kodansha edition

The prequel to the number one bestselling Attack on Titan and winner of the Diamond Gem Award for best manga continues! OLD SCORES SETTLED The expedition to test out the Vertical Maneuvering Equipment and keep the Survey Corps alive is plagued by rain and poor conditions- nerves are tense when emergency flares are shot off, and supply wagons turn up destroyed. On top of that, one of the nearby Titans is none other than Ogre, the one who killed Kuklo's mother on the fateful day of his birth! Can he avenge her memory, save the Survey Corps, and convince Xavi that the Titans can be overcome? FINAL VOLUME!

Source: Penguin Random House API