“This Is Us” stumbled just a bit as it entered its home stretch Tuesday night, but its Valentine’s Day performance was still enough to make it a big bright spot for NBC, coming in with a 2.4 rating in the 18-49 demographic and 8.97 million viewers with just two more new episodes left in the season. “The Wall” led into “This Is Us” with a solid 1.4 in the demo and 5.73 million viewers. “Chicago Fire” pulled in a steady 1.5 and 6.71 million viewers.

Over on CBS, which (as usual) dunked on everyone else in terms of total viewers, “NCIS” drew a solid 1.8 in the demo and 15.05 million total viewers. “Bull” weighed in with a 1.3 and 10.57 million viewers. “NCIS: New Orleans” notched a 1.2 and 10.22 million viewers.

One interesting note: If you look at the number of 18-34 viewers as a percentage of the “NCIS” audience, that percentage is lower than many other shows on the night. But “NCIS” — typically thought of as the show you watch when you’re at your parents’ house — last night drew the same 18-34 rating as NBC’s “Chicago Fire” — a 1.0 — tying for second place in that demo for the whole night and showing that when you cast a wide enough net, you get more of just about everybody.

ABC’s Tuesday comedy block mostly dipped from last week. “The Middle” held steady with a 1.5 in the demo and 6.25 million viewers, but “American Housewife” ticked down to a 1.4 and 5.27 million viewers. “Fresh Off the Boat” lost a couple tenths with a 1.0 and 3.64 million viewers. “The Real O’Neals” came in with a 0.8 and 2.89 million viewers. “Marvel’s Agents of S.H.I.E.L.D.” drew a 0.7 and 2.17 million viewers.

Fox’s Tuesday appears to have found its level. “New Girl” held with a 0.9 and 2.14 million viewers. “The Mick” ticked up slightly to a 1.0 and 2.47 million viewers. “Bones” brought in a 0.8 and 2.98 million viewers.

The CW aired a “Tough Mudder” challenge at 8 p.m., which drew a 0.3 in the demo and 770,000 viewers, and followed it up with a “The Flash” repeat that brought in only a slightly smaller crowd (0.2, 709,000).

In late night, “The Late Show with Stephen Colbert” is continuing its winning streak over “The Tonight Show Starring Jimmy Fallon” in total viewers, according to Nielsen’s metered market overnights. Colbert on Tuesday drew a 2.8 household rating to Fallon’s 2.2, though Fallon is still ahead in the 18-49 demo in these preliminary results, 0.7 to 0.6.

As a reminder, many of these series will see lifts of 50% or more once viewership within three and seven days is counted. However, most of those gains won’t translate to the ratings guarantees networks make to advertisers.