ABC’s fantasy-themed reality series “The Quest” opened to small numbers on Thursday, a night that saw fairly typical results for the original programs on all the broadcasters — led as usual by CBS’ “Big Brother.”

According to preliminary national estimates from Nielsen, “The Quest” averaged a 0.7 rating/3 share in adults 18-49 and 2.8 million viewers overall in the 8 o’clock hour, placing it behind repeat CBS comedies as well as a repeat of NBC’s “Hollywood Game Night.”The network did the same demo rating in the 8 o’clock hour last week with drama “Black Box.”

The show, a carefully crafted fantasy world in which 12 contestants compete for the honor of being the One True Hero, garnered generally positive reviews but viewers didn’t seem all that interested, at least on Thursday night. Viewership also dipped in the second half-hour.

“The Quest” comes with a strong pedigree, as it executive producers include Bertram van Muster (“The Amazing Race”) and Mark Ordesky (“Lord of the Rings”).

ABC followed up the reality show with drama “Rookie Blue” (0.9/3 in 18-49, 4.5 million viewers overall) and docuseries “NY Med” (0.9/3 in 18-49, 5.5 million viewers overall), with both about average. “NY Med” was up some in total viewers, drawing its largest overall audience since its June 26 premiere and again winning the 10 o’clock hour by this measure.

CBS opened with encores of “The Big Bang Theory” (1.6/7 in 18-49, 7.2 million viewers overall) and “The Millers” (1.2/5 in 18-49, 5.4 million viewers overall) and then saw a typical spike at 9 p.m. with “Big Brother” (2.1/7 in 18-49, 6.2 million viewers overall), which matched last week’s score and was the night’s top program in 18-49 and 25-54 rating (2.5/7). A repeat “Elementary” (0.7/2 in 18-49, 3.6 million viewers overall) closed things out for the net.

CBS won the night in 18-49 (tied with Univision), 25-54 and total viewers. Univision, coming off a first-place 18-49 finish in the July sweep for a second straight year, was led Thursday by “Lo Que la Vida Me Robo”

At NBC, a repeat of “Hollywood Game Night” (1.0/4 in 18-49, 4.0 million viewers overall) did about as well as a firstrun episode, placing second among the Big Four in all key categories. “Welcome to Sweden” (0.7/3 in 18-49, 2.6 million viewers overall) was down a tick from last week, and “Working the Engels” held steady (0.6/2 in 18-49, 1.9 million viewers overall). At 10 p.m., “Last Comic Standing” (1.1/4 in 18-49, 3.3 million viewers overall) held steady and once again beat out its ABC and CBS competition in young adults.

Fox aired a repeat “Sleepy Hollow” (0.5/2 in 18-49, 1.8 million viewers overall), followed by an original “Gang Related” (0.7/2 in 18-49, 2.3 million viewers overall), which matched last week’s rating.

Preliminary 18-49 averages for the night: CBS and Univision, 1.4/5; NBC, 0.9/3; ABC, 0.8/3; Fox and Telemundo, 0.6/2; CW, 0.1/0.

In total viewers: CBS, 5.4 million; ABC, 4.3 million; Univision, 3.5 million; NBC, 3.2 million; Fox, 2.0 million; Telemundo, 1.4 million; CW, 0.6 million.