Book One for Sorrow — Helen Fields

One for sorrow, two for joy
Edinburgh is gripped by the greatest terror it has ever known: a lone terrorist is attacking victims across the city, and no one is safe.
Three for a girl, four for a boy
In their positions, intelligence officer Ava Turner and police department head Luke Callanach face death every day. But when it becomes clear that every bomb is a trap meant to kill them too, the possibility of facing it starts to feel all too real.
Five for silver, six for gold
As the death toll rises each day and the terrorists' methods grow more horrific, Ava and Luke must race against time to uncover who is behind the attacks—or pay the ultimate price...