Dominic Da Vinci spends some time in nearly every episode this season dealing with his attempt to become chief of police. He also works with the mayor intermittently on a safe injection site, something Da Vinci has been wanting since the series started. At the end of the last episode, he heads in to the interview for the police chief job.
After watching six seasons of this, I've finally registered another significant point of realism: the police officers we watch have drawn their guns twice in six years. And the only officer who ever fired a gun suffered from a couple years of depression (he seems to be recovering now). Amazing: you can have a great show without constant gunplay.
Da Vinci continues to be a hot-headed asshole whenever people do things he believes are wrong. He always does what he believes is right. He's always been sympathetic to the families of those who've died, and he's a loyal friend - including to a councilor who's done a couple things Dominic disagrees with. It's representative of the series: people aren't one-note, they're damn complex.
And while all this is going on, people continue to die and their deaths are investigated. The series remains very well written and acted.