This is book 4 in the Slough House series.  Once again Jackson Lamb and his crew of “slow horses” find themselves embroiled in international intrigue and terrorism.  The case is personal for River as it begins with an attempt on the OB’s life, leading to connections to the long ago past, which at this point is almost lost to OB.   Really well written with a plot that intricately twists and turns involving an engaging cast of both recurring and some new characters.  This is a great series and I am really enjoying it.