After losing her right arm and left leg in the battle, Izana has them replaced with prosthetic limbs, while Tsumugi is put in a special regeneration chamber. Nagate feels gloomy due to Tsumugi's condition, but he cheers up later on when he learns from Mozuku that Tsumugi is fully recuperated. Nagate and Izana decide to help Tsumugi see more of Sidonia by exploring some abandoned tunnels. Meanwhile, Sidonia arrives at the Lem Star System to confront the Gauna Hive Cluster and fires its reverse thrusters to slow down just as Nagate and Izana are inside the tunnels, nearly killing them. However, they find a way to allow Tsumugi to look at the residential district through her probe, much to her joy. Back to the dormitory, Nagate finds that his room was allocated to another cadet and his possessions was dumped outside his room. He then shocks Izana with a call by asking if he can stay at her house overnight.