SUNDAY

Togetherness 10:30 p.m., HBO

The series is from the busy yet low-key Duplass brothers, the producing-directing-acting pair who’ve had a hand in a ton of independent movies in recent years, and it’s really good. It’s good not necessarily because the story line is original; it’s a familiar tale of two couples in LA, one married with kids and struggling, the other attracted to each other but unable to connect. It’s good because the writing is sharp and unflinching, comic and yet dramatic, as we watch a marriage reach a crisis point. And it’s good because the acting is excellent, by Mark Duplass and Melanie Lynskey as the married couple but especially by Steve Zissis and Amanda Peet as the maybe couple.

MONDAY

Becoming Mike Nichols 9 p.m., HBO

Directed by Douglas McGrath, “Becoming Mike Nichols’’ is an edited version of two conversations between Nichols and theater director Jack O’Brien a few months before Nichols died in 2014. Nichols tells stories about the making of “Who’s Afraid of Virginia Woolf’’ and “The Graduate.’’ (For more on the show, see Page N7.)

TUESDAY

Frontline: Chasing Heroin 9 p.m., WGBH 2

This episode of “Frontline’’ looks at America’s heroin epidemic through the experiences of four addicts in Seattle.

WEDNESDAY

Broad City 10 p.m., Comedy Central

It has been a great few years for women in TV comedy. Two of the best — Abbi Jacobson and Ilana Glazer — have just returned for season three of “Broad City.’’ The pair have created a stoner, slacker duo that is comparable to Lucy and Ethel, Mary and Rhoda, and Laverne and Shirley — but remarkably different and highly original. Abbi and Ilana are demented and codependent and crude and endlessly endearing as they survive in the belly of the urban beast.

THURSDAY

VikingS 10 p.m., History

One of the coolest things about “Vikings,’’ which just returned for season four, has been its ongoing religious themes. The show is a beautifully filmed saga with lots of political game-playing and action sequences, but it’s also a look at the conflicts between paganism and Christianity, as well as a few people — including the show’s hero, Ragnar — who cross the boundaries between them. This season, the story line jumps with more regularity to Wessex and Paris, where Ragnar’s brother, Rollo, is now married.

FRIDAY

American Masters 10 p.m., WGBH 2

Fats Domino had 63 pop hits and 59 R&B hits in the 1950s and early 1960s. This episode of “American Masters’’ takes a look at his career.

SATURDAY

Nightmare Nurse 8 p.m., Lifetime

Sometimes, you just need to read the title to know everything. And other times, you decide to watch the movie anyway, to verify that your predictions were correct. In “Nightmare Nurse,’’ a couple hires a live-in nurse to care for the man’s injured leg, but things don’t go smoothly.MATTHEW GILBERT