Naoto and the other K4 members head to Karuizawa for Advanced Railway Security Force Training. Naoto is excited to hear that they'll have a course on operating an EF63 electric locomotive. Aoi accompanies him in shooting lessons and strength training, saying she doesn't want him to slow her down as they'll be working in railway security together, but Naoto tells her he's aiming to be an engineer instead, leading to an argument.