Because I'm By Your Side is the 178th chapter of Hiro Mashima's Fairy Tail. The King orders Byro to quicken the extraction of the giant Lacrima. When Erza Knightwalker is about to execute Lucy. Happy and Carla save her and they escape. They decide to go save Natsu and Wendy, but instead get surrounded by the Exceeds imperial guards and the Royal guards.