Spirals (螺旋) is the 21st chapter of the manga series.
Synopsis[]
Chito and Yuuri attempt to climb up the inside of a tower to the next level, but are stopped a hole in their path. They use some scaffolding on the outside of the building in order to continue upwards with their Kettenkrad, but it buckles under their combined weight and collapses. Chito and Yuuri barely make it off with the Kettenkrad before it falls entirely.