When the gang's sausages go missing, and they discover gnashed bicycle wheels and one of Gnasher's teeth, it seems like there's only one suspect. But Dennis refuses to believe that Gnasher is to blame. Gnasher realizes he's being set up by Clawdia, Walter's ultra sneaky cat, and has to find a way to prove his innocence.
Series 1: 38. Bertie's Backbone
Dennis and the gang train Bertie in the art of standing up to people so he can rebel against Walter's bossiness - but they train him too well and he becomes a dangerous reb ...