A live retelling of “On Golden Pond” failed to generate much ratings heat for CBS on Sunday, a night that was a flop in general for the broadcast nets.

Fox won every half-hour in key adult demos and ABC prevailed in total viewers by dominating the night’s final two hours, according to Nielsen prelim nationals, but the major nets combined for a measly 48 share in adults 18-49 — marking the first time on record that the Big Four have failed to attract at least half of the available 18-49 audience on a sweeps Sunday. A year ago, ABC, CBS, NBC and Fox combined for a 58 share in the key demo.

“On Golden Pond” (prelim 11.9 million viewers, 2.5/6 in A18-49) certainly didn’t help, becoming the Eye’s second Sunday-pic flop in as many weeks with well-known stories (last week’s “Murder on the Orient Express” averaged 10.5 million viewers and also grabbed a 6 share in 18-49). Production of the Ernest Thompson play, starring Julie Andrews and Christopher Plummer, finished last in its 9-11 p.m. time period in both total viewers and all key demos.

“Pond” didn’t get much lead-in help, as “60 Minutes” (prelim 2.2/7) and “Touched by an Angel” (prelim 2.9/8) fell to all-time firstrun lows in 18-49 and combined for a fourth-place finish in the Eye’s target demo of adults 25-54. CBS was off by 35% in the 25-54 demo vs. the opening Sunday a year ago (prelim 3.3 vs. 5.1).

ABC was down by 29% in adults 18-49 vs. last year (prelim 4.5/12 vs. 6.3/17), although “The Practice” (prelim 6.4/16) limited its losses to 3%. The drama (prelim 17.1 million) and quizzer “Who Wants To Be a Millionaire” (prelim 18.1m) each won their hours in total viewers, but the television premiere of “Tarzan” drew a surprisingly tame 10.5 million viewers.

Sly Fox

There was better news for Fox and NBC, with the former improving on a year ago by 4% in adults 18-49 and the latter roughly matching its perf.

Fox’s “The Simpsons” (prelim 7.0/20) and “Malcolm in the Middle” (7.0/18) were Sunday’s top programs in 18-49, helping the net to a 3-share victory over NBC. Two bonus repeat episodes of “The Simpsons” from 7 to 8 also helped, while “The X-Files” (prelim 6.3/15 in A18-49) won its hour but was off by 10% vs. a year ago.

The Peacock net had its most competitive Sunday since the Golden Globes in January, as a decent lead-in from NBA playoff action and the network preem of three-hour theatrical “U.S. Marshals” (prelim 12.6m, 5.2/13 in A18-49) left it second in adults 18-49 for the night (projected 4.7/13).

NBC pulls in the young

A strong Sunday has helped NBC and Fox finish atop the demo leaderboard for the week of April 23-29, according to projections. When Nielsen issues the final numbers today, NBC is expected to be on top with a 4.8/14 in adults 18-49, followed by Fox (4.3/12), CBS (3.8/11), ABC (3.5/10), the WB (1.5/4) and UPN (1.4/4).

CBS will edge out NBC in total viewers, with ABC third.

Through four nights of May sweeps, NBC remains comfortably on top in the demo (projected 5.0/15) while CBS enjoys a sizable lead in total viewers (13.2 million).