From the introduction:
Alexei Samsonov, who had achieved the rank of Major in the Red Army and would soon reach Colonel, sat relaxing in a small, private beerhall; in spite of its size it was the finest in all Berlin. The two men at the table with him were also officers, but they wore the uniform of the German Reichswehr. They had been drinking freely. They were not talking about their work. They were in too pleasant a mind to talk about their work, and it was forbidden anyway. The two men in Reichswehr uniforms asked him playfully to describe the girl they had seen on the Alexanderplatz, using Ancient Greek, and Samsonov replied that he would be glad to do so, but that he would first have to decline a certain noun in all its forms; he did not see his adjutant behind him until the man whispered in his ear.