When two grade-school boys beg for a playdate, what’s a conscientious Connecticut mom to do?

That’s why uptight Stephanie Smothers (Anna Kendrick) starts hanging out with glamorous Emily Nelson (Blake Lively), sipping martinis in the afternoon and exchanging intimate secrets while their respective sons - Miles (Joshua Satine) and Nicky (Ian Ho) romp around.

Certainly, on the surface, they’re unlikely best friends. A widowed, stay-at-home single mom, Stephanie does a perky, Martha Stewart’ish video blog, giving household hints and recipes, while career-driven Emily works in Manhattan, doing PR for a high-powered fashion designer (Rupert Friend), while her British novelist husband Sean (Henry Golding) copes with writer’s block.

Sophisticated Emily is obviously amused by Stephanie’s awkwardly puritan demeanor, while prim, self-deprecating Stephanie is dazzled by Emily’s caustic, irreverent quips and fabulously chic lifestyle.

But when Emily suddenly goes missing after asking Stephanie the “simple favor” of picking up Nicky and watching him for a few hours, a sinister mystery kicks in, along with a possible murder.

When Stephanie drops the bumbling goofiness and goes into detective mode, she forms a relationship with Sean, who describes inscrutable Emily as “a beautiful ghost, never entirely there.”

Paul Feig (“Bridesmaids,” “Spy,” “The Heat” and that “Ghostbusters” reboot) loves directing women, and that’s obvious in Jessica Sharzer’s overly convoluted, Hitchcockian adaptation of Darcey Bell’s 2017 novel of the same title.

But he’s delivering a mixed message, trying to combine disparate elements into a comedic thriller. Both Anna Kendrick and Blake Lively deliver strong performances, although Henry Golding’s diffidence disappoints, particularly after his suave role in “Crazy Rich Asians.”

The strong supporting cast includes Andrew Rannells as a snarky dad and Bashir Salahuddin as a nosy detective with Jean Smart and Linda Cardellini as remnants of Emily’s femme fatale past.

On the Granger Movie Gauge of 1 to 10, “A Simple Favor” scores a slyly seductive, suspenseful 7. It’s surprisingly stylish, suburban neo-noir.