Harmless, enjoyable fun with a really interesting central premise (the best friend is a ghost who has died in mysterious circumstances), which would be fascinating to explore in more depth in future novels featuring these characters. The only irritation was the author's self conscious misuse of the 'they' pronoun when referring to the character of Alex, who identifies as non binary. It is one thing for a character to consider themselves a 'they', but when the author does too, it repeatedly causes a moment of confusion for the reader and spoils the flow of the narrative.