Blue Bloods, the new cop show that’s carved out an audience on Friday nights, moved to Wednesday this week, and proved why viewers like this series. A 25 year-old case involving the death of a child brought up a lot of memories and a lot of emotions in Tom Selleck’s Frank Reagan, but, superb actor that he is, Selleck made sure Frank communicated those emotions — sadness, anger, frustration — without any excessive displays.

In the hour’s other plot, Donnie Wahlberg’s Danny Reagan investigated the murder of a woman who worked for a posh escort service. Unlike Selleck, Wahlberg’s way of achieving a quality performance is to have Danny simmer just below the boiling-point. He satisfies a viewer’s desire for the hardboiled element of a cop show, spitting out lines like, “Let’s go scoop up this piece o’ garbage” before apprehending a suspect.

Blue Bloods is a family saga; the Reagan family extends from a beat cop (Will Estes) to an assistant district attorney (Bridget Moynahan). It’s a gimmick that, during a good week such as this one, transcends gimmickry. The show’s signature moment is the family dinner in which everyone gathers around to eat and argue about the cases they’re working on.

This week, the quarter-century-old case gnawed at Frank’s memory and conscience; brooding and relentless, Frank seemed to share a bit of the bleak worldweariness Selleck gives to his other fine current character: Jesse Stone, in the annual TV-movies Selleck makes. But Frank is distinguished by the fact that he’s a family man who’s accepted a big job — New York police commissioner — and will put up with the bureaucracy if it helps the police all the way down to the street-cop level. But this week, Frank’s impassive face betrayed the strain of a case that got away from him, that haunted him into the present. That betrayal was the measure of a fine performance. Selleck’s climactic scene, in which Frank drew out a confession from the murderer in an interrogation room with quiet, reasoned fury, was pretty great.

Do you watch Blue Bloods? What do you think of the series?

RATINGS UPDATE: You fans will be glad to know that in its Wednesday premiere, Blue Bloods won its time period and scored higher ratings than the show it replaced, The Defenders.

Twitter: @kentucker