Joe Country by Mick Herron

 If Spook Street is where spies live, Joe Country is where they go to die. (Quote from Amazon)

Slough House and its inhabitants move on in a life that is always more of the same.  Same falling down workplace, same colleagues, same make work, same Jackson Lamb who rules over it all.  

But some things happen.  River's grandfather, the OB, has finally died after a long career as a spy and having raised River.  Lech is the newest Slow Horse and he is determined to find out what got him assigned there and who was behind it.  Catherine Standish is starting to buy booze again after years of being dry.  And River's father, the man Jackson Lamb hates above all others, is still out there.

When River sees his father at the cemetery at his grandfather's funeral, he takes off chasing him but once again his father manages to escape.  But this time the group and Lamb have an idea where he is heading.  Louisa Guy has taken on the task of finding her former lover's son who has disappeared.  River's father seems to have been hired to find him as well.  Lamb sends the Slow Horses out to find the son and capture River's father but he has hired guns with him.  Will everyone return?

This is the sixth Slough House novel in the series.  These books are an addiction.  I'm so glad I waited until there were nine of them as I've listened to them as quickly as I can, starting the next as soon as I finish the former.  I've listened to them as Gerald Doyle is the best narrator match I can imagine.  He can hit the sly notes, show the determination of the agents even when wrong and bring Jackson Lamb to life in a way that is perfectly done.  Lamb pretends not to care but his agents are his charge and no one hurts his charges.  This book is recommended for mystery and spycraft readers.