Marvel’s synergistic efforts remain one of its assets, but transforming a supporting player in “Captain America,” played by Hayley Atwell, into the star of a limited ABC series was inordinately opportunistic even by its standards, and as it turns out, a pretty smart bet. That’s because the combination of the British actress and post-World War II setting make the Marvel-branded vehicle, “Agent Carter,” considerable fun, and in some ways more promising than the series it’s replacing, the uneven “Agents of SHIELD.” While there’s no assurance this spinoff will have legs, the opening salvo is worthy of a hearty “Hail, ‘Carter.’”

Shrewdly using a clip from “Captain America” to intro the show (a cheap way, if you think about it, to get Chris Evans into your series), the program picks up in 1946, with Atwell’s Peggy Carter working as a spy for a covert agency, albeit one in which the male-dominated hierarchy doesn’t take her seriously.

“I didn’t know our government had such good taste in secretaries,” a suspect sneers, while her boss (“Boardwalk Empire’s” Shea Whigham) tells Peggy to step outside so she won’t have to sully her delicate eyes by seeing a colleague employ what might be euphemistically described as enhanced interrogation methods.

That promises to change, however, when charges of treason are leveled against inventor/industrialist/playboy Howard Stark (Dominic Cooper), none other than Iron Man’s dad, who Peggy knows well from her dealings with Cap. So she quickly finds herself surreptitiously investigating an elaborate threat, with an assist from Stark’s soft-spoken butler Jarvis (James D’Arcy), a clever nod to the Avengers’ comic-book valet, who is fine with espionage work as long as he’s home and in bed by 9 o’clock.

The period setting not only gives the series an enticing look – the trappings throughout are impeccable, including Christopher Lennertz’s muscular score – but also ups the glamor quotient. When Atwell goes undercover sporting a blond wig, it’s like Veronica Lake on the prowl, only with a solid right hand.

Indeed, even the idea of a butt-kicking female hero (an ABC staple of late, from “SHIELD” to “Revenge”) is heightened by the unabashed sexism of the time, filtering the show’s “Alias” vibe through that first stab at “Wonder Woman” with Lynda Carter, before the latter was foolishly transferred from the ‘40s into a contemporary frame. (ABC and Marvel will seek to boost the premiere, incidentally, with another synergistic garnish — namely, a teaser for the upcoming movie “Ant-Man.”)

The proximity to World War II, threat from SHIELD foe Hydra and onset of the Cold War augur no shortage of villains, with another Brit, James Frain, occupying one of the black-hat roles. In the caution-flag column, the two-hour premiere dangles plenty of questions and answers relatively few of them, and the pacing is less crisp in the second half.

“Agent Carter” is being billed as a limited event, one essentially keeping “Agents of SHIELD’s” seat warm until the program returns in March. With a little luck, though – and help from international appeal – ABC just might find itself with the kind of utility player who, whether trying to save the world or merely plug a hole in primetime, certainly comes in handy in a pinch.