what happen in chapter 26 and 28?

Chapter 26- The journey becomes a little harder each day as the inclines grow evermore steep. At times the men are almost perpendicular with the ground they tread. Axel thinks back to a few days prior when he got lost in the echoes of the cavern and is thankful for the stream he discovered. Sadly, at the end of this chapter the stream has dispappeared.

Chapter 28- Axel is seaprated from his uncle and the guide. They can hear him because of the electrical currents that manage to run along the granite walls like acoustics. Axel ended up moving alond by himself, called goodsbye to his uncle, and soon was falling. His landing resulted in unconsciousness when he hit his head on a rock.