Just when you think you understand television, it changes.

Seems just the other day I was writing about TV storytellers embracing brevity, offering documentaries as short as 10 minutes in duration.

Today, ESPN launches a 20-hour epic, "Basketball: A Love Story" (7 p.m.). To put that in some perspective, that's twice as long as all three "Godfather" movies combined!

This 10-part documentary will offer 62 short stories about the NBA, ABA, college basketball, the women's game, and international basketball, and will explore the social, cultural and political impact of sport as discussed by hundreds of experts and legends.

"Love" features 165 interviews, and profiles basketball's most prominent figures, from Bob Cousy to Kobe Bryant.

"Love Story" will unfold in two-hour dollops on every Tuesday until Oct. 30, before taking a week off and concluding Nov. 13.

- The first rule of making a TV show is to keep the drama on screen.

Now in its third season, "Lethal Weapon" (9 p.m., Fox, TV-14) has broken that rule several times.

Last spring saw the firing of Clayne Crawford, who played Martin Riggs, the hotdog partner of family man Roger Murtaugh (Damon Wayans).

Rumors swirled that Crawford had created dangerous conditions on the set. Wayans said he suffered a head injury during the filming of an episode directed by his co-star.

Season three began with Seann William Scott's arrival, as Murtaugh's new partner, Wesley Cole.

In a strange case of art imitating life, tonight's episode is about Cole trying to balance work and family life.

That's odd, because just last week, Wayans announced his intentions to leave "Lethal Weapon" after production was complete on season three's 13th episode.

Among his concerns were the time spent on the set away from his own family.

He also cited the grueling demands an action series placed on his 58-year-old body.

It remains to be seen if Wayans leaves the show, or if this is just a negotiating ploy for better hours throughout the length of his six-season contract.

Whatever transpires, Wayans makes an interesting point. Perhaps series involving frequent car chases, gun fights and continual explosions are the province of younger performers.

- Because when you're "Home Alone" (10 p.m., ID, TV-14) watching a network dedicated to stoking fear in female viewers, there's nothing like an hourlong look at violent intrusions.

Particularly after you've just watched the fifth season premiere of "Evil Twins" (9 p.m., TV-14).

TV-themed DVDs available today include "Killing Eve" season one.

Tonight's season premieres

- A visitor overstays her welcome on "The Flash" (8 p.m., CW, TV-PG).

- The school puts safety first on "Black Lightning" (9 p.m., CW, TV-14).

Tonight's other highlights

- Tracee Ellis Ross hosts the 2018 American Music Awards (8 p.m., ABC), scheduled to present a special tribute to the late Aretha Franklin.

- Meredith Vieira hosts "The Great American Read" (8 p.m., PBS, TV-PG, check local listings).

- Major League Baseball Divisional Playoffs (8 p.m., TBS).

- A pattern emerges after the death of 18 women on "FBI" (9 p.m., CBS, TV-14).

- Kate's procedure worries the family on "This Is Us" (9 p.m., NBC, TV-14).

- "The Circus" concludes on "American Experience" (9 p.m., PBS, TV-PG, check local listings).

- "Inside the NFL" (9 p.m., Showtime) takes stock of the season after five weeks.

- A Naval officer expires on "NCIS: New Orleans" (10 p.m., CBS, TV-14).

- Max challenges a wealthy patron on "New Amsterdam" (10 p.m., NBC, TV-14).

- EZ's star rises on "Mayans M.C." (10 p.m., FX, TV-MA). This series has been renewed for a second season.

Series notes

A Navy SEAL's home is bombed on "NCIS" (8 p.m., CBS, TV-PG) ... Blind auditions continue on "The Voice" (8 p.m., NBC, TV-PG) ... A health scare for Polaris' baby on "The Gifted" (8 p.m., Fox, TV-14).

Late night

Jimmy Fallon welcomes John Cena, Maggie Gyllenhaal and H.E.R. on "The Tonight Show" (11:35 p.m., NBC) ... Emma Thompson, Elle Fanning and Lykke Li visit "Late Night With Seth Meyers" (12:35 a.m., NBC, r).