A Hundred Billion Stars, a Hundred Billion Lights 3: Those Who Defect Episode 15

Walter von Schönkopf, worried that his superior Otto Frank von Wahnschaffe, the regimental commander of the Rosen Ritter who is leading the Alliance reconnaissance mission, might have encountered Imperial forces, sets off with his trusted subordinates to find him. Along the way, they discover that Hermann von Luneberg, who is revealed to be the former regimental commander of the Rosen Ritter, is commanding Imperial troops on Van-Fleet 4-2. Although they manage to rendezvous with Wahnschaffe, they are soon ambushed by Luneberg's troops and are only able to retreat after suffering considerable losses, including the life of Wahnschaffe.