There is much to commend this series but it falls short of greatness.
The plot and the mystery is well done and the script and acting are very good throughout. However, you can't help feeling you have seen it before. The reason for this is the plot line has been dropped into a paint by numbers tv detective drama structure with so my of the usual tropes present. For example, the retiring old policemen, the strained relationship with the partner, teenage child who is rebellious and feeling neglected to mention just three. However, despite this it is watchable amd is also designed for bi fe watching. Deliberately so in that each episode leaves you with a cliffhanger to lead in to the next episode. The only problem is that by the time you get half way though you realise that the cliffhangers don't really amount to much at all.
Another flaw, as mentioned in other reviews here is that while the main plot reaches a conclusion and you find out who is doing what etc, it still leaves a few loose ends unexplained or unresolved. This deliberate in an attempt to justify an2nd series. Except that although these thing are unresolved they aren't going to tempt you to want more and so it all seems flat.