Morgan and the gang in the Croton Filtration site's upper tunnel begin a critical turn with the mole. As they steadily close in on their goal of mining 3745 feet, the gang has little margin for error. But mid-way into the turn the mole's navigation system goes down, making it so they may have to go forth 'blind'. While on Manhattan's west side, young sandhog Jason Durkin commits the rookie tunnelworker's gaffe known as hanging a steel and his fellow hogs don't let him off the hook easily. Back at Croton, the mole mines the final stretch of rock in the upper tunnel as Morgan plans an important explosion which will allow the sandhogs to back the mole out of the tunnel. As Morgan and his gang wrestle the jackleg drill, the sandhogs at the #7 subway line site get a reminder of how dangerous the jackleg really is when Jason is injured by the mammoth machine. Finally, Morgan and gang attempt a tricky double explosion, out in front of the mole.