In the coasts of Hamburg in Germany, a gang of sewer rats steal food as a group of cats led by Curl plan to get rid of the rats led by Big Rat. The plan failed, but the rats were forced to retreat as the other rats pursued the cats, with Zorba (a black cat) injured. During the escape, The cats encounter Bubulina, which Zorba is enamored and leaves. Meanwhile, at the ocean, a petrol ship sinks leaving a lot of petrol in the sea. The next day a seagull flock starts looking for fish in the sea, they dive in and stay there until their leader spots the petrol flood, he warns the rest of the flock, but one of the seagulls named Kengah doesn't hear it and gets dirtied by the petrol. She survives the accident but has trouble with flying. She flies over the city until she falls on a woman's garden, right on top of her cat Zorba. Being disgusted by the petrol taste Zorba refuses to eat her. Kengah asks him three promises that he must do if she doesn't survive. The first one is that when she lays her egg he must not eat it, the second one is that he must take care of it until it hatches, and third is that he would teach the newborn how to fly.