THE KNICK. 10 p.m. Friday, Cinemax.

In its first season, Cinemax's period drama "The Knick" was the scariest medical show on television, more frightening even than one about the Seattle hospital run by adolescents.

A patient showed up missing a nose from syphilis. Others died in startling ways. Electricity proved to be dangerous, and nurses and doctors played with a newfangled X-ray machine as if it were an office copier, unaware, in 1901, that overexposure to their new toy might kill them.

As Season 2 begins tomorrow night, "The Knick" is as engrossing and disturbing as ever, and the medical gore's only a small piece of it.

Director Steven Soderbergh's lighting may be early 20th century, but that light's diffused through a prism of 21st-century sensibilities. Accompanied by an electronic score, "The Knick" can feel very much of the moment. And it's kind of an ugly moment.

Anti-immigrant sentiment. Political and corporate corruption. A yawning gap between rich and poor, and, of course, large dollops of racism and sexism.

Beyond reminding us of the limits that persist in a medical system we like to think of as cutting-edge, creators Jack Amiel and Michael Begler expand their focus this season to mental illness and addiction, the treatments of which prove as startling as those for the physical ailments of the day. As one character puts it, "Psychiatry is a very new field, and things always look worse at the beginning."

Clive Owen returns as Dr. John Thackery, who was chief surgeon at the fictionalized (but not wholly fictional) Knickerbocker Hospital before his addiction to cocaine got out of control. As the season opens, he's still in rehab, such as it is, and nurse Lucy Elkins (Eve Hewson), his lover and enabler, is counting the days to his return.

Andre Holland ("42") is Dr. Algernon Edwards, a Harvard-educated surgeon who has his eye on Thackery's job, but whose prospects aren't bright: He's a black doctor in a hospital that serves (and largely employs) only whites.

With the bleeding-heart Thackery at least temporarily out of the picture, the hospital's board of directors is hoping to move the Knick uptown, following the money and freeing it from the burden of treating the poor just outside its doors.

On one level, "The Knick" is a beautifully filmed soap opera with a medical backdrop. Characters fall for one another, mostly unwisely, and the path of true love is inevitably rocky.

Season 1 introduced us to the hospital's corrupt admininistrator, Herman Barrow (Jeremy Bobb), to a nun and midwife (Cara Seymour) who performed abortions on the side, and to a love story involving Dr. Edwards and socialite social worker Cornelia Robertson (Juliet Rylance) that was far more dangerous than anything we've seen on "Scandal."

We also met Mary Mallon (Melissa McMeekin), the original "Typhoid Mary," whose story may have consequences this season.

Thackery's past dissipation could grow tiresome - so many opium dens, so little time - but the series soars whenever he and Edwards are cooking up medical marvels in the skunk works they run out of the hospital.

"If people knew what you actually did in here, they wouldn't trust you to give them a f---ing aspirin," remarks one character on hearing one of their exchanges.

He's not wrong. But then on "The Knick," what you do know isn't any more likely to kill you than what you don't.