Does it bring luck or rather bad luck, this little black tomcat who wanders through the cozy suburb where Rosa Schätzlein and Frido Schulz are at home? At first neither of them notice the animal at all, as they are far too busy with other things: Especially with themselves. Because although Frido and Rosa have known each other since their studies, have been neighbors for ages and Frido's wife is Hanne Rosa's best friend, they are like cats and dogs and never miss an opportunity to fight. The former law student is a thorn in the side of Frido in particular: She made it to the position of a successful lawyer while he had to take over his father's modest electronics business. But then a real stroke of fate overtakes the family man, notorious choleric and lay lawyer: Hanne dies. Frido and Rosa notice how empty their lives are without Hanne.