The Crimson Tower (紅蓮の巨塔 Guren no Kyotō?) is the 2nd chapter of the 3rd volume and the 9th chapter overall of the Attack on Titan: Before the Fall manga, written by Ryō Suzukaze and illustrated by Satoshi Shiki.
Overview
Carlo orders the surviving Survey Corps soldiers to retreat while he helps Kuklo enact his plan. Briefly crippling the Titan, Carlo leads it to a damaged wagon filled with gunpowder and Kuklo ignites it. Engulfed in flames, the Titan is stunned but eventually continues to chase them. Fortunately, it was incapacitated long enough for Carlo and Kuklo to safely reach the Wall.
Summary
As Kuklo confirms that he can enact his plan, Carlo Pikale orders the Survey Corps to begin retreating to Shiganshina District. As the Titan begins to pursue them, Carlo rides up and cuts its leg, causing it to lose its footing. As the Titan turns to them, Kuklo asks Carlo if it is okay for him to be leaving everything to Kuklo, but Carlo tells him that, in such a situation, they are all comrades in their common fight against the Titans.
The Titan is engulfed in flames
Riding towards the Titan, Carlo cuts through its leg again. As the Titan keels over, Carlo orders Kuklo to take the horse's reigns, and begins cutting the Titan's outstretched hand. As they begin retreating, Carlo informs Kuklo that it is time to enact his plan. As the Titan pursues them, Carlo and Kuklo approach the wrecked cart Kuklo was hiding in, and as they jump over it, Kuklo drops his canister of gunpowder into the cart; the resulting explosion engulfs the pursuing Titan, causing it to roar in pain.
Turning to see if their plan worked, Kuklo is horrified to see that the Titan is still alive but Carlo tells Kuklo to ignore it. As they return towards Shiganshina, Kuklo turns to look at the Titan again and is shocked to see it still able to move as it stumbles out of the flames. It soon regains its footing and resumes chasing the two.
The Garrison prepares to fend off the Titan
Atop Wall Maria, members of the Garrison watch the explosion as they prepare their cannons. As the Survey Corps begins to enter the gates of Wall Maria, a few stop to watch Carlo and Kuklo, who are approaching with the Titan close behind them. The Garrison members begin to fire upon the Titan, as Carlo and Kuklo enter Shiganshina, and Wall Maria's gates are closed behind them. As Kuklo listens to the cannons, he wonders if they will kill the Titan, but Carlo informs him that the cannons will not hurt it; this is why the Survey Corps must fight to the extent that they do.