Shades of Blue starts its second season with the kind of high stakes, gasp-worthy drama that made parts of its first season edge-of-your-seat TV: Harlee Santos (Jennifer Lopez) has just snapped the neck of her abusive ex, and now she's got to dispose of the body.

Apart from her very good rom-com work, Lopez really shines when she's either trembling in all-consuming fear or kicking butt, and in Season 2's opener she's doing the visceral fraught-with-fear thing that's delightfully suspenseful. From here though, the momentum stops and starts, and that's one of the biggest issues with Season 2.

Shades of Blue Season 2 begins with Jennifer Lopez burying a body

In the first three episodes, we're dealing with the aftermath of Harlee's murder of Miguel (Antonio Jamarillo) as well as the fallout from her betrayal of Lt. Wozniak (Ray Liotta) — head of the Dirty Cop gang she belongs to. Now aware she's the rat in the group, Woz no longer trusts her, and that will have devastating effects as her problems mount. FBI agent Robert Stahl (Warren Kole), who's been creepily pursuing Harlee while using her in an investigation, is still pulling strings in her life. And when both Harlee and Woz soon learn that they were just smaller fries in a bigger investigation that goes deeper than even they knew, they'll be running to break out of a tiny maze created by their own lies and secrets. New characters — including Julia Ayres (Anna Gunn), an ex-cop and friend of Woz's who's running for mayor with ties to the Mafia — join the mix, making Woz and Harlee's lives again complicated, dangerous and out of their own control.

How's all that work? Sometimes decently, and sometimes not so great. Shades of Blue's initial sell was that it wasn't just another cop show, but chunks of the first three episodes feel like exactly that. Even though it's not a crime-of-the-week procedural but an exploration of betrayal and abuses of authority, it gets mundane, with characters shouting (or growling, in Woz's case) everything they have to say and stock-in-trade scenes at the police station, where numbing exposition takes place.

Jennifer Lopez as Det. Harlee Santos, Shades of BlueJennifer Lopez as Det. Harlee Santos, Shades of Blue

Shades of Blue hits its sweet spot when it gives us intense confrontational scenes where big secrets get revealed, and make no mistake, there are some juicy ones in the first three episodes. Getting to them though, frequently means pushing through a tangled web of overlapping "Wait, who double crossed who again?" stories that get repetitive and a little boring. That Woz, a frightening beast who'd murder you without much of a second thought, would let Harlee's major betrayal go without even attempting to ruin her life is but the first of a few puzzling pieces we have to shove aside in order to play along.

Of course, there's much more to come after the third episode — the point at which Harlee is now looking like tasty rat meat to Stahl, a Mafia leader and possibly Ayers without the protective cover of Woz, who may do more than just yell at her for not being the friend he thought she was. All that, as well as the slow corrupting of Harlee's daughter Christina (Sarah Jeffery) and her colleague/rookie cop Michael Loman (Dayo Okeniyi) and an internal investigation happening, means Shades of Blue certainly has created a great set up that'll yield more of the arresting moments it does well. It's just getting to them that can feel like a trial.

Shades of Blue begins Season 2 Sunday, March 5 at 10/9c on NBC.