‘Samantha Who?’ flirts with its initial promise

For A while last year, it felt that, unlike most network sitcoms, “Samantha Who?” would be occupied with the bigger questions. Can you trust what people tell you about yourself? Is there an authentic core hiding underneath years of callouses, or is everyone really making it up as they go along? If you lose your memory, can you get your childhood back? And what about your virginity?

Samantha Newly (Christina Applegate) had been in a car accident that resulted in retrograde amnesia -- she recognized no one, remembered nothing but the basics -- and the first few episodes unfolded under clouds of doubt. New Sam (or was that Original Sam?), it turned out, was warm and inquisitive and openhearted, everything Old Sam was not. But New Sam jumped right back into her old life -- same friends, same job. In the beginning, she questioned them, but over time, she took it for granted that this was the life she was best equipped for.

The existential themes didn’t hold, though. By midseason, “Samantha Who?” had regressed to something conventional. Sam’s amnesia became a backdrop against which traditional sitcom material played out, but didn’t color the narrative in a way to significantly tweak it. This was a letdown for a promising character and also for the show, which was drained of its originality. A couple of episodes, in which New Sam tried to undo some of the harm that Old Sam had done to others, had the uncomfortable hokeyness of “My Name Is Earl.” And the persistent folk-wisdom voice-overs were a little too redolent of Meredith Grey.

But even though the show, which returns Monday (ABC, 9:30 p.m.), skipped out on its higher calling, it managed to deliver something maybe almost as radical for a sitcom: a nuanced and healthily developing mother-daughter relationship. As mom Regina, Jean Smart was luminous and uproarious in equal measure; she earned an Emmy last month for her performance. Regina is needy, manipulative and tragicomic but also invigorated by her second chance at being a good parent. Before Sam’s accident, the two hadn’t spoken for two years; flashback scenes hinted at a tumultuous, unpleasant relationship.

Such was, and is, one of the charms of “Samantha Who?”: Sam’s amnesia has forced everyone around her to do more than his or her share of remembering, and the show has been best when that work leaves its mark, as it does on Regina. Other characters, though, are unmoved. Sam’s ex-boyfriend Todd (Barry Watson) rarely came off as anything other than meek, and her best friend, Andrea (Jennifer Esposito), was coquettish without depth.

For the most part, Applegate succeeds in holding the show together. She has considerable comedic skill -- great timing, appealing and slightly awkward physicality -- and her daffiness was never a liability. (On the episode in which she fell in love at warp speed with a new man, who promptly dumped her, she was thrilling, her raw feelings conveyed in exaggerated facial expressions that practically filled the screen.) Plus, in scenes where she portrayed Old Sam, who was styled to look like midperiod Heather Locklear, she was naturally vicious. New Sam was a saint, mostly, but one began to wonder whether that was really the act.

This week, Sam finally moves out of her parents’ house and back into the apartment she owns but had let Todd stay in, inexplicably. Still, she can’t ignore the primal pull of family. After New Sam discovers that Old Sam was a talented dancer, she pairs with her mother for a local dance competition (a wink, perhaps, to the unfounded rumors that Lance Bass would have a male partner on “Dancing With the Stars” this season). The pair’s final dance, shot in a style that suggests “Twin Peaks” far more than any current sitcom, is borderline sublime, the awkward twosome played not for comic relief but with emotional respect. It’s not enough, but it’s a step.