Two out of the three plotlines for “Mr. Brightside” parts 1 and 2 were pretty drama-free: Alli had to trust her parents to like Dave for who he really is, and Holly J and Fiona found a way to give Dawn her kidney money. So, mostly happy endings in Degrassi-land. Even Drew and Katie seemed to have a growing flirtation. AND THEN DREW STARTED CAGEFIGHTING.