There wouldn't be an actress worth her socks who would turn down a role in a La Plante written script, and the Commander herself is one of La Plante's usual intriguingly flawed but very human roles.
Commander Claire Blake (for reasons never revealed or explained)
falls for a convicted killer (well played by Hugh Bonneville)
and conducts an affair with him, which quickly becomes public knowledge among her colleagues.
At times her aloofness when dealing with/speaking to her subordinates/colleagues makes one believe there's some polar bear DNA involved somewhere there deep in Claires being !
Despite the obvious shortcomings of the first episode, the standard improves dramatically in the following 2 film length series 2 Black Dog and series 3 Virus.
It's not Lynda La Plante's job as creator to explain why Claire Blake behaves the way she does,but it is encumbent upon her not to stretch the realms of possibility too far. The sister with cancer,wallowing in self pity,is one such example of the over stretching of belief (and just plain over acting) and is one character we could have done without.
DCI Mike Hodges,played by Matthew Marsh and a rival of Claire's was involved in the shooting of a suspect and the doctoring of the security video which captured the whole event. This tale of crime and coverup, runs through the three stories as a sub plot, which in the end comes crashing into Claire's fight to keep her job in the final episode. I don't want to give too much away of the storyline, just suffice to say the Commander as a series does - despite an indifferent start - becomes a riveting series well worth watching.
Amanda Burton and Matthew Marsh are both superb, as is Hugh Bonneville. Give it a try.