Light Shines on the Darkness is the 37th overall episode of Tegami Bachi
Noir appears to have recovered to his former self, Gauche; however, he walks away from Lag. Lag goes after him but is blocked by Roda. A large group of gaichuu, Lao-Lao, arrives to attack them. Lag and Zazie's attacks are not able to fend off Lao-Lao. Unbeknownst to them, the traitorous capital inspectors are controlling the gaichuu to attack them while Cabernet gets away.
Soon, however, Niche arrives to restrain Lao-Lao with a new ability using her hair, and Lag destroys the gaichuu in one shot. Roda tries to follow Noir but she falls through a crevasse but Lag grabs her in the nick of time. Roda does not understand why he would save her; however, Lag explains that he feels Roda is the same Roda that was Gauche's former dingo, and encourages her to keep fighting to protect her master.
Pledging loyalty, Lag takes quite a risk; however, Roda frees herself of Lag's grip and seemingly falls to her death, lamenting that she is Reverse's Roda. However, she leaves Lag the letter bullet that she stole from him—trusting that he can help Noir. While Zazie fends off Cabernet, Lag goes after Noir to attempt in reviving his memories of being Gauche.
When Connor arrives with a comatose Sunny, Lag becomes disappointed with what Reverse and Noir have done. Spurred by his emotions, Lag's spirit amber charges up. Noir fires a shindan at him but Lag easily erases it. Lag declares that he will erase him from existence, and then Lag shoots Noir, knocking him unconscious.
Cabernet is attracted to the heart Lag radiates and grabs both him and Noir with gaichuu ropes. Lag is initially unable to target Cabernet's weak point, but Noir awakens and directs him to attack together with him. Cabernet is hit by both shindans but gets away. In the aftermath, Lag is told Connor will stay with Sunny until she awakens, while Zazie goes after Cabernet. Lag brings a comatose Noir back to the Bee Hive where Dr. Thunderland would diagnose his condition. Soon, it can be seen that Aria and Sylvette are glad that Lag has brought back "Gauche," and therefore, Lag feels that for a brief moment Gauche has come back to him.