[Credit Huaisang this, he patiently does a circuit around with Xichen, just to prove this library is messing with them on a fundamental level. He gestures broadly at the shelves, pointing accusingly at the guilty books when they return.]

It didn't! You were standing right here, reading a book with a white spine! [but he didn't see anything more incriminating than that, and now the book is gone, so congratulations on being spared that particular mortification--] Now where is it? Er-ge, you see?

[Rude of the shelves, frankly. He waves his hand again, deciding:]

This place must be full of spirits.

[Bored ones. Not resentful ones.]