Well, in English, when we talk about more than one'story', we use the word'stories'. It's a common rule for many nouns that end with 'y' preceded by a consonant. We change the 'y' to 'i' and add 'es'. So, for example, we say 'I have read two stories this week'.
Yes, a novel can be made plural. Just like with most nouns, when you have more than one, you add an 's' to make it 'novels'. For instance, 'I have read several novels this month.' shows the plural usage.
I'm not entirely sure specifically which 'chimney boy story' you mean. But generally, it might tell of a boy's adventures in the chimneys. He could be exploring the rooftops and chimneys of a city, perhaps meeting other interesting characters along the way, like other chimney sweeps or people living in the attics. It could also be a story of his growth, starting as a timid boy and becoming more confident through his experiences in the chimneys.
The plural of'science fiction' is'science fictions'. This is a common way of forming plurals in English for compound nouns. We treat'science fiction' as a single unit when making it plural. For instance, we might say 'There are many great science fictions that explore different futuristic concepts. These science fictions can range from stories about space exploration to those about artificial intelligence and how it might impact our future society.'