Napoleon, returned defeated from Russia, wages his last battles in the area around Dresden in 1813. His opponents use secret diplomacy to position themselves in order to redistribute power. In this explosive situation, Hofrat von Block, director of the famous art collection in the Green Vault, gets caught in the webs of power politics. His deputy is murdered, all traces point to Block. The court counsellor is no murderer, but he has an embarrassing secret. In order not to blow the whistle on his double life, he agrees to supply information to the Prussians. Block's adolescent daughter Ariane is horrified when her father is arrested. She is determined to prove his innocence and begins to investigate. She is supported by her piano teacher, the musician and poet E.T.A. Hoffmann. But the more the two of them find out, the clearer it becomes that Block cannot be innocent at all.
