"Ignition," Part 5 of 6, features a guest appearance by another prominent hero. The fastest man alive struggles to protect Keystone City's police force as the identity of their assailant comes to light. While the hero seeks justice, a lawless rogue also pursues the killer. Adding to the tension, the hero and his wife endure an unpleasant visit from the new K.C.P.D. Rogue Profiler.