“Indebted,” NBC’s new sitcom, has the virtue of a top-of-the-line cast. Now if only it could figure out what to do with them.

Fran Drescher makes a return to network comedy as half of a couple (along with Steven Weber) who’ve blown through their savings on luxuries with no clear plan on how to spend rest of their lives; they move in with their son (Adam Pally) and daughter-in-law (Abby Elliott). Together, these two couples contain four comic ringers — and yet the plots they’re forced through feel so sparklessly rudimentary that the actors (especially Pally) can’t quite be blamed for sleepwalking through them.

The show feints towards treating its characters as antiheroes but won’t in its first few episodes meaningfully commit — ultimately, they’re good, if confused, folks who care for each other. The precise midpoint between juicily nasty and wholesome is a tricky balance to strike, and “Indebted” doesn’t get there, toggling back and forth between its perspectives on the characters depending on the scene. When they’re mean, they’re too mean — as in an episode where their vicious gossip habit threatens the relationship of Pally’s character’s sister (Jessy Hodges). And when they’re nice, that’s an overcorrection to all the meanness.

This now represents the second sitcom on which an alumnus of “Happy Endings,” a show that did manage to strike that complicated tone, is hauled in to serve as a sort of cue for the audience of the type of show they should expect, and here as on Damon Wayans Jr.’s “Happy Together,” the performance and writing both feel too diffident to achieve the intended effect. Drescher is the only person who seems to be trying — her performance, unlike her castmates’, is effortless in a good way. Her work a reminder of an old-fashioned sitcom sparkle that “Indebted,” halfheartedly trying to be cynical, could maybe use more of.