How did I end up in one of the most dangerous distircts of Cagliari looking for moules

“We’re looking for Enzo,” said Roberto, a native from Cagliari, big guy with a big smile; he knew how things work here. We were in a bar in a strange part of Cagliari, capital city of Italian island Sardinia. “I can show you where he lives,” stood up a man in his sixties, covered by tattoos and followed by enormous black dog. “Perfetto,” was happy Roberto, “maybe he has stuff for us.”
The “stuff” were fresh moules, Roberto decided he wants to cook a good plate of spaghetti with them for our little group. We were a bunch of strangers brought together by Couchsurfing: Roberto was hosting me, my boyfriend and Fausto, an actor from Rome whose every third was “eccezionale!” in his house in the center of Cagliari.
We followed the man with black dog through the small and dirty streets where you could see rubbish everywhere and where the silence was a bit too suspicious. Roberto’s original plan was to get fresh moules from the market, and why not showing us the atypical one? When we arrived to the place there was nothing left but some boxes and leftovers of the food. Luckily, Roberto knew who sells the best fish so we went to find his house to ask if he has any, just as simple as that.
We were in front of it, Roberto knocked on the door. Man who opened was small, thin, wearing a white tank top and ripped jeans. “What do you want?”he asked and didn’t seem very pleased when he saw us. You could see in his posture that he wasn’t someone you could mess up with. “Do you still have some fresh moules?” kindly and optimistically asked Roberto. Enzo replied after a moment of silence: “ No, I sold everything. I have just some frozen calamari, that’s all.” Roberto thanked him and we went back to the bus station. On our way back we passed the street full of abandoned buildings with graffiti on it. When we almost reached the station we heard a sneaky voice offering us some drugs; cocaine, heroin and marijuana.
I asked Roberto: “Is that a joke?” And as if nothing special was going on he calmly replied: “No, I don’t think so.” While we were waiting a bus to go to the supermarket he apologized for missing the true experience of atypical market, and offered us to go another time. That time we were not really aware of the fact that we were hanging around in one of the most dangerous districts of the city. Anyway, the spaghetti with moules were so good in the end that Fausto said “Eccezzionale!” few times in a row. In the end, we were all alive and full of good italian pasta.