Glitch tries to teach the Grimbots by drawing on a chalkboard. Before he can finish, his last piece of chalk snaps and the grumpy Grandmaster demands the Grimbots find a fresh supply. Meanwhile, the Go Jetters arrive at the White Cliffs of Dover in England, to cheer Kyan as he finishes a cross-channel swim, but a large cloud of dust blocks his way to the shore. On the beach, Lars and Foz find the Grimbots mining the cliffs with a big drill, causing a big crack to spread across the rock face. Can they cut the power and make the cliffs safe again?