The Gate Keeper by Charles Todd

His sister has just married and left on her honeymoon and Ian doesn't know what to do with himself.  He decides to go for a drive.  He doesn't know where he'll end up but maybe it will get him out of this helpless feeling of no place to call home.  Instead, he drives up to a standing car with a woman in distress.  The driver has been shot and killed...

William Morrow and Edelweiss allowed me to read this book for review (thank you).  It will be published January 17th.

He begins sorting things out and working on the case even though he's not been assigned.  Scotland Yard finally sets him up as their local contact.  Then another man is found shot through the heart.  Who would kill these folks who had no enemies?

As he searches through the past, he finds that a book seems to connect them all.  It's an antique book about apples.  He can see no significance in it but it seems everyone who touches it ends up dead.  As he keeps tying the webs together, he finds there probably is a good reason. The killer was someone who surprised me.  

This mother-son team writes excellent mysteries and this is another in the series that pleases.  I'd like to see Ian find a love interest but he's a very good detective and interesting fellow even now.