Episode Title:Rusty and the Boulder.Episode Description:A new quarry is being built under a mountain, where a huge and mysterious boulder dwells. Rusty worries that the boulder is watching him. The next day, the boulder falls and chases Rusty, Rheneas, and Skarloey before narrowly missing Percy and demolishing a shed. The Fat Controller then orders the quarry to be shut down and the boulder to be moved to a hill, where it can do no more damage.