At the Kriegsmarine headquarters, Kessler talks to engineer Holzer, who is responsible for the secret plan to build a research facility on the bay. They talk about using Polish specialists who know this reservoir well during the construction of the center. Franz comes to the command. During a conversation with Ilse, he manages to obtain a secret document regarding the resort being built on the bay. He is summoned by Kessler. He learns from him that his brother, Otto, died at sea during combat.