Well, it would be the possessive pronoun "its". Although I'm sure you could find some examples if you looked for them, I don't think that's often used, partly perhaps because neuter things don't often possess other things. I suppose there are some exceptions, like animals perhaps, or some collective nouns (like a company) if you are treating them as singular rather than plural, which might possess other things. But even then, I think most people would say, to use a different example since "books" doesn't really work in this case, "I saw that tabby cat again. My garden seems to be one of its hangouts" rather than "My garden seems to be a hangout of its".