“It’s $50,000. It is not the kind of thing that everyone can just go out and get.” – Margaret Hall

If you need a great movie about blackmail, this is it. The Deep End (2001) opens with a seedy nightclub scene in Reno (Mom attempts to bribe a man with the promise to stop seeing her son) and then settles into the unassuming everyday family life of waterfront Lake Tahoe. The mercurial Tilda Swinton (“Michael Clayton”) gives a Meryl Streep performance as the protective mother whose husband is away on Naval command. I say that because I think this film is a prime example of why Swinton is as great an actress as Streep. Here she plays a mom who covers up a killing that her son might have accidentally committed. Somehow we observe a dozen complex emotions and facial expressions at once by a virtuoso actress who is multi-faceted in every way.

Anybody who has ever been to Tahoe knows the community is circular around the lake. The road leads two ways, that’s definite. The police find the body of the night club owner Darby (Josh Lucas), and there’s mom driving by the scene marked by police tape. Hours later, she gets a visitor named Alek Spera (Goran Visnjic) at her door who demands $50,000 or he will go the police with a sex tape featuring Darby and Margaret’s son. Yes, the tape of homosexual fornication is a tad too graphic which may be the reason why “The Deep End” doesn’t get played on basic cable. You will have to seek it out on Netflix or a video store.

Swinton plays the blackmail scene with outrage, collected temper and concern for her son – she will do anything to get him out of trouble and to not embarrass him about his sexual preferences. He is 17 years old with a bright college future, equating to, Margaret will take the blame if she has to. Or she can pay and the problem will supposedly go away. Cashing out on loans and pawn shops doesn’t bring Margaret enough bounty, though, so what do you do when you can only come up with half the money?

This was the second film by the directing team of Scott McGehee and David Siegel. Their tremendously effective new film “What Maise Knew” is their fifth film after nearly twenty years in the biz. They know concise camerawork, how to utilize natural settings to make it specific, and how to edit for effective tension. “The Deep End” has purpose and engagement scene after scene, familiarizing us with Tahoe (so if you’ve never been, you still get a thorough portrait locked in your mind), and then what rips our hearts as viewers is witnessing the deepening chasm of mistakes by Margaret that festers more trouble as well as altering the terms of blackmail.

There is a terrific moment outside genre predictability when Margaret has a domestic problem, and Alex, who was there to do a shakedown routine on her, gets involved conducting CPR on a sick family member. This inexorably pulls down his façade as a tough mobster and it turns him into an understanding human being. The problem is that Alex’s associate Nagel (Raymond Barry) is less than sympathetic. The subterfuge must go on, money is money and it is heartless.

99 Minutes. Rated R.

TWISTED DRAMA / THINKING MAN’S THRILLER / AFTER HOURS VIEWING

Film Cousins: “Blood Simple” (1985); “After Dark My Sweet” (1990); “Notes on a Scandal” (2006); “Mother” (2009, South Korea).