The Key to a Killer
A Ruby and Cordelia Mystery Book #3
by Olivia Blacke

Release date: October 20th, 2026
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I received a complimentary ARC copy of The Key to a Killer, A Ruby and Cordelia Mystery Book #3 by Olivia Blacke from NetGalley and St. Martin’s Press /Minotaur Books in order to read and give an honest review.
…All in all I really enjoyed the book, the writing is entertaining, the characters are lovable, and if you have kept up with the series thus far, this is the payoff you have been waiting for. It is cozy, clever, and I absolutely adore the series.…
In the third entry in the series, we get another round with Ruby and her ghostly roommate Cordelia and as always this series is just so much fun. By book three, their dynamic feels way more lived in. Ruby is less hesitant, more confident and definitely more willing to dish out some much needed bluntness to Cordelia, which gives their banter a sharper edge.
This installment really steps up the personal stakes because Cordelia is finally investigating her own murder. Watching them piece together that trail of clues makes the keeps even the biggest mystery reader on their toes. Even if the slow start with the backstory takes a minute to push past but it quickly gets interesting as Cordelia starts recovering fragmented memories from that fateful day. The tension amps up as the two follow a winding trail of clues that puts several people from her past under suspicion. Add in Cordelia’s recently released brother, Ian, showing up at inconvenient times and a shady corporate competitor lurking in the background, and Ruby has her hands full trying to crack a deeply personal case before trouble finds them first. The mystery itself had me guessing until the very end, and the unique dual POVs of Ruby and Cordelia elevate the standard cozy mystery to a whole new level.
As I have mentioned before the real magic of this series remains the bonding between the living and the dead. I still really enjoy the quirky friendship between the two one being probably twenty plus years older and having experienced life quite differently. Cordelia is still always looking out for Ruby and seems to finally not be the lonely person she was when she was alive. Their creative ways of communicating, almost reading each other’s minds, is fun and makes for a witty banter that just adds to the story. There are also some really touching moments between Cordelia and Ian. My only negative, other than the albeit neccessary rehash at the beginning, is the frequent reminders of the limitations that Cordelia experiences being a ghost, which, while necessary, sometimes slows the pacing a bit, but honestly it is a tiny issue for an otherwise fun, engaging, and genuinely quirky read.
All in all I really enjoyed the book, the writing is entertaining, the characters are lovable, and if you have kept up with the series thus far, this is the payoff you have been waiting for. It is cozy, clever, and I absolutely adore the series. I am a bit concerned now Cordelia’s murder has been solved, it has an air of finality to it but I am definitely not ready to say goodbye to these characters just yet, so I hope there are more stories ahead for this dynamic duo. If you like a non-scary ghost story with a great mystery and an incredible odd-couple friendship, I would highly recommend it.









