Restaging Grey’s Anatomy as Mean Girls sounds like something you’d dream after eating a extra-large triple-anchovy pizza. And yet, in one of life’s pleasant little surprises, it turns out not be a stomach-convulsing nightmare but a totally endearing experience, as you will discover if you watch Emily Owens, M.D.

Debuting on The CW Tuesday night, Emily is a comedy-drama starring Mamie Gummer ( Evenings) as a professionally promising but socially doomed intern at a Denver hospital. Known in high school as Pits for the nervous perspiration in which she nearly drowned every time she had to speak in public, Emily is still the sort of catastrophic geek to whom complete strangers feel comfortable sneering “Loser!” and even friends say stuff like, “You’re way cooler than you look.”

She was looking forward to her internship as a chance to leave the past behind, the moment when she would “blossom into the secure, confident, kick-ass person I was always meant to be.” And, possibly, her chance to finally confess her feelings to her med-school crush, Will Collins (Justin Hartley, Smallville), now her fellow intern.

That happy glow lasts about 30 seconds, until Emily discovers that her high-school nemesis, Cassandra Kopelson (newcomer Aja Naomi King), is also an intern. They instantly revert to their roles as bully and victim, with Cassandra disclosing Emily’s old nickname and inept social history, as well as setting her own sights on Will.

A show with the twin themes that life is high school and the past cannot be escaped sounds inordinately depressing, but the writing and performances on Emily rise far above the apparent limitations. Gummer, who may remind you a bit of a younger, ditzier Meryl Streep (who, coincidentally, is her real-life mom), is astonishingly appealing as she takes social punch after punch but stays on her emotional feet. And King, while deliciously villainous, nonetheless shapes her character into something more interesting than the stereotypical class bitch.

There’s also a lot more to Emily than social water boarding. The show’s various gossipy subplots — particularly those involving Tyra Dupre (Kelly McCreary, White Collar), an intern whose chief-of-staff father “wanted a son, got a lesbian” — are all entertaining. So much so, in fact, that you sometimes forget that Emily is a medical drama with unexpected life-and-death moments that can feel like a punch in the stomach. Any show that can simultaneously work on your gut and your heart is worth a look.