Two TV police shows debut this week, but one shows the ending first

What would it take to become commissioner of the New York Police Department within 10 years of graduating from the police academy?

What kind of person could accomplish so much - and all before his 35th birthday?

What drive, determination, force of will? And what sacrifices? What ruthlessness?

That's the fascinating premise of the new CBS police procedural Golden Boy, which premieres Tuesday at 10 p.m. It's one of two new prime-time cop shows this week - the other is the TNT reality series Boston's Finest, which premieres Wednesday at 9 p.m.

Golden Boy is the latest addition to CBS' cop-glutted schedule and, after Blue Bloods, its second about a New York City police commissioner.

Series writer-creator Nicholas Wootton (NYPD Blue) clearly is banking on Golden Boy's unique premise to help it float over the stiff competition: He gives us the story's ending in the first minutes of the pilot.

The series opens seven years in the future, when Walter William Clark Jr. (British actor Theo James) is appointed the youngest police commissioner in New York history.

Each episode is bookended by brief scenes showing Clark as the commissioner: he looks tired, decrepit, decades older than his tender 34 years. We then see, in flashbacks, how the hunky twentysomething Clark - sprightly, young, keen, excitable - got there.

It all begins when Clark, then only three years in the force, becomes a media sensation when he takes down a pair of bad guys and saves a hostage and his partner - all after taking a bullet himself.

Riding high on the good PR, the top brass tell Clark he can have any assignment he wants: He chooses homicide.

It's all downhill from there.

Clark is crestfallen when he finds out he's been partnered with Detective Don Owen - a raggedy, overweight veteran detective two years away from retirement - and not the squad's star cop, Tony Arroyo (Kevin Alejandro).

Owen, who is played with Yoda-like wisdom and infinite patience by the great Chi McBride (Human Target), immediately sees Clark for what he is: a man driven to succeed no matter what it takes. And a man so haunted and twisted by demons from his childhood, he's forgotten about telling right from wrong.

As the detectives solve each case - Bonnie Somerville (NYPD Blue) and Holt McCallan (CSI: Miami) round out the squad - Clark betrays more about his dark past and makes ugly decisions to feed his naked ambition. Owen tries to temper him, to steer him away from the dark side.

Wootton recently said Clark's character was inspired by David Fincher's take on Mark Zuckerberg in The Social Network as a man with "drive and ambition and this sort of thoughtless forward-thinking I-don't-care-who-gets-burned ambition."

It's a terrific idea. But it doesn't quite measure up to its potential.

The police cases writers dish out each week are little more than standard Law & Order fare, while the discussions between Clark and Owen feel like after-school specials on ethics.

Golden Boy asks a great deal of James, who was cast after the more robust actor Ryan Phillippe dropped out. The Brit, best known in America for a stunning guest appearance as a randy Turkish diplomat in Downton Abbey, is solid, but his Clark comes off as a weaselly manipulator who's difficult to like. He lacks the sort of charisma that makes screen antiheroes so fascinating.

Over on TNT, Boston's Finest is that very rare, precious thing: A reality show that's actually watchable.

Executive-produced and narrated by Blue Bloods cop Donnie Wahlberg, Boston's Finest is a docudrama that follows members of the Boston Police Department as they go about their daily lives on the streets and at home.

Given unprecedented access by the authorities, show producers follow officers from every part of the department as they run down suspects, chase thieves, serve warrants. And we stay with them after each shift, as they eat with their families or take their kids shopping.

The cases aren't always exciting - there's a lot of waiting around - but the people we meet are always interesting and are depicted with class. This is Cops for people who hate shows like Cops.