On a night dominated by the NCAA basketball tournament finals (8 p.m., CBS), ABC offers viewers a chance to catch up with “Samantha Who?” (8:30 p.m., ABC).

“Samantha” stars Christina Applegate in the title role as a pretty young lawyer who emerges from a coma with no idea that she has lived her whole life as a selfish monster. Her new life calls for a balancing act between her desire to change and the gravitational pull of her old ways.

This absurd situation has provided Applegate with some fine opportunities for screwball comedy, but tonight’s midseason reopener seems forced and at times a little sad.

Samantha pines for Todd (Barry Watson), the boyfriend she treated so shabbily in her past, but he has moved on and has a new girlfriend, Chloe (Kiele Sanchez, “Lost”). Will Samantha learn to live and let live, or will some of her old, bad habits come out of hibernation?

Whatever happens, it’s clear that the writers have begun to exhaust the comedy’s thin but daring premise.

¢ The eight-part series “America’s Port” (9 p.m., National Geographic) looks at the complex beehive of activity at the Port of Los Angeles, where more than 16,000 people work every day as an endless stream of container ships offload the goods that Americans import from around the globe.

Created by the team behind “Ice Road Truckers” and “Deadliest Catch,” this series does a good job of explaining the complexities and dangers of life on the waterfront. But its sprawling cast of characters prevents the kind of intimate, intense dramas shown on “Deadliest Catch.” “America’s Port” will air every Monday over the next seven weeks.

Tonight’s other highlights

¢ A patient has problems bigger than his waistband on “House” (7 p.m., Fox).

¢ “Designed to Sell” (7 p.m., HGTV) looks at ways to renovate kitchens with real-estate value in mind.

¢ Jennifer Saunders (“Absolutely Fabulous”) takes a crack at the racetrack on “Top Gear” (7 p.m., BBC America). A second episode (8 p.m.) follows.

¢ John keeps a promise to a dying partner on “New Amsterdam” (8 p.m., Fox).

¢ Rosanna Arquette guest stars on “Medium” (9 p.m., NBC).