Coco is the well-respected, if somewhat easily startled, Chief of Police in Buenos Aires. Alberta is his more sensible cousin. Together they crack the cases that confound the puzzling city. Coco Carlomagno is trying to avert a national disaster. La Bella Cucharita, the highly strung world-famous opera singer, is due to make her return to the stage after an unfortunate nerve-wracking incident - but a strange message has her rattled. Who on earth would send La Bella Cucharita mysterious notes on the eve of such an eagerly awaited performance? Luckily Coco is on the case, and with a little help from his logic-loving cousin Alberta, he can discover just who is behind the quivering quavers.