From their uncannily similar one-sheets to their like-minded plots involving a brassy loose cannon taking charge of a scout troop, DNA from the delightful 1989 Shelley Long comedy "Troop Beverly Hills" runs undeniably through the veins of "The Boss." At their core, both films are good-hearted, but this blissfully R-rated vehicle for Melissa McCarthy (2015's "Spy") carries a raucously acidic sting that would make Long's Phyllis Nefler blush. Writer-director Ben Falcone (2014's "Tammy") and co-writers McCarthy and Steve Mallory have woven a narrative in need of a little more focus and follow-through, but they do succeed where it most counts. First and foremost, this is a very funny movie, sometimes uproariously so. Inspired by a character she originated during her time performing in L.A.-based improv group The Groundlings, McCarthy has once again breathed irrepressible life and spirit into a truly original creation.

Michelle Darnell (Melissa McCarthy) is the 47th wealthiest woman in America, a thought-unstoppable CEO of three Fortune 500 companies who receives a rude awakening when she is arrested for insider trading. Following a five-month stint in federal prison, Michelle is dismayed to learn she has lost everything—her companies, her reputation, her mansion, her possessions, and all her money. With nowhere else to turn, she convinces her overworked, underappreciated former assistant, single mom Claire (Kristen Bell), to let her stay with her until she gets back on her feet. Feeling sorry for herself can only last so long, and soon Michelle's innate cutthroat drive to succeed has her scheming her next venture. Inspired by Claire's delicious homemade treats and Claire's daughter Rachel's (Ella Anderson) Dandelion troop, Michelle recruits a group of get-getter young girls and spearheads Darnell's Darlings, a for-profit brownie business. Heartened by her old boss' offer to make her a 50-50 partner, Claire agrees to join forces on this endeavor. For someone who, as a child, was constantly rejected by foster families and raised in an orphanage, Michelle still has trust issues—a lifelong hang-up which threaten to dismantle Darnell's Darlings as she gets closer to Claire and Rachel.

There is an outrageously funny scene in "The Boss," set at a five-star restaurant where Michelle is determined to enjoy her pufferfish cuisine, that is so perfectly written, performed and edited for maximum comic impact it scarcely would matter even if the rest of the film fell flat (it doesn't). If the top priority of a comedy is to make the audience laugh, this one more than succeeds; on two separate occasions, including the one mentioned above, tears streamed down my face while uncontrollable hysterics and gasps for oxygen took over. As often is the case with movies where a lot of gags and one-liners are tossed at the screen in hopes of sticking, not every joke hits its target. More do than not, though, and the pretty consistently amusing results do wonders to smooth over a predictable plot trajectory and obligatory ploys in the third act to redeem Michelle and her unsavory-at-best, awful-at-worst behavior.

Melissa McCarthy is a comedic phenom, an ebullient showperson, and a supremely fine actor too often underrated for the nuance and truth she brings to even the most ribald of characters. She is the rare performer with the ability to make likable and sympathetic a person as crass, belittling and dishonest as the savvy, manipulative, turtlenecked Michelle tends to be. McCarthy will do anything to sell the material she's working with, and the joyful spark she gives her every moment on screen is infectious. As Claire, Kristen Bell (2014's "Veronica Mars") is the so-called straight man of the proceedings, asked to react (as most level-headed people would) to Michelle's outrageous outward demeanor. Bell is warm and natural, as is Ella Anderson (2015's "Unfinished Business") as daughter Rachel; one watches and automatically wants to root for them. As the fellow tycoon who got away, Peter Dinklage (2015's "Pixels") has fun playing Michelle's back-biting ex-lover Renault, wanting to take his adversary down even as his fires continue to burn for her. Tyler Labine (2011's "Rise of the Planet of the Apes") is an affable, down-to-earth love interest for Claire, as office coworker Mike, while Annie Mumolo (2011's "Bridesmaids") is terrific as snooty Dandelion mother Helen, her expletive-heavy tête-â-tête confrontations with McCarthy a riot of sharp dialogue and line delivery.

As an overall story being told, "The Boss" knows where it is going but is a tad scattered getting there. As fun as the picture is, there are missed opportunities in more deeply exploring Michelle's past and the uncompromising, egotistical path she initially took to claw her way to domination. Fortunately, McCarthy so fully and effectively embodies this ginger-haired force of nature she makes up for these developmental shortcomings. The supporting characters—like Michelle's scorned mentor Ida Marquette (Kathy Bates) and Dandelions troop leader Sandy (Kristen Schaal)—are more noticeably underused, set up for presumable payoffs that never come. The young troop ladies are also mostly shoved aside, with only Rachel and the tall Chrystal (Eva Peterson) receiving any notable defining traits. What "The Boss" is never at a loss in providing, however, is jovial, unpretentious entertainment. This is Michelle Darnell's show above all else, and she wouldn't have it any other way.