Amazon calculates a product’s star ratings using a machine learned model instead of a raw data average. The machine learned model takes into account factors including: the age of a review, helpfulness votes by customers and whether the reviews are from verified purchases.
It keeps you wanting to find out what is happening. The main protagonist, Lionel, has a secret past that has apparently been suppressed due to childhood trauma. There is scope for a sequel and I would be interested in the follow up.