This young beautiful woman, Christina Mattern, is truly in love with the banker Rolf, as private detective Max Wunderlich personally convinced himself of. And it’s not about her eyes, full of tears and tender sadness. It turns out that two years ago Christina gave Rolf her priceless diamond so that he could pawn it and improve his financial affairs. There was so much loyalty, trust and desire in this act of hers to save her lover from harm! But she didn’t. In broad daylight, in the very center of Frankfurt am Main, a banker is killed with two shots at point-blank range. Unhappy Christina instantly becomes both lonely and poor. She has no money other than the missing diamond; she barely scraped together a private detective. Detective Wunderlich soon finds out that the killer is a young, frail blond man in black glasses. This seems to be a serious lead. But then news comes that the banker's wife, Frau Brigitte, will now inherit ninety percent of the assets of the bank that her late husband headed. The investigation seems to have reached a dead end...