Thomas Seifert was killed in his study, wife and child are missing. Three years earlier, Thomas incurred lasting brain injury from which he recovered physically, but never regained his sunny personality and turned recluse, badly straining his marriage and last friendship. Thomas Seifert showed interest only in collecting old letters, some of which are the only things missing at home. Teen apprentice roofer Jannis Brüggmann caused Seifert's injury by not securing a hammer, had no insurance, moved in with his strict grandfather and was condemned to all Seifert's medical costs plus a monthly wage-substitute, which the knave could never pay off while Thomas lived, effectively preventing any social life. Nils however finds a surprising relevance in the missing letters, bringing the flee market trader into the picture.