Movie review: 'Instant Family' marries laughs, tears before devolving into crass comedy

“Instant Family” - ★ ★ ½

For once, an advertising tagline accurately summarizes a film: “Instant Family: Just add chaos, laughter, awkwardness, mistakes and love.”

“Instant Family” instantly sweeps us up into a smart, funny and realistically unpredictable adoption movie.

Then, inexplicably, Sean Anders' wonderfully fresh and sassy foster family film abruptly devolves into a crass, conventional comedy.

That happens at exactly the moment when Pete (Mark Wahlberg) and his wife, Ellie (Rose Byrne), step out of character to physically assault a school janitor they suspect of taking advantage of their 15-year-old foster daughter Lizzy (the charismatic Isabela Moner, who starred with Wahlberg in “Transformers: The Last Knight”).

“Instant Family” never recovers from this tonal misstep. It gets worse when an uncredited Joan Cusack creates an uncomfortably embarrassing cameo as a needy neighbor who serves no narrative function, except to desperately troll for nonexistent laughs.

But before “Instant Family” goes the way of the Hindenburg, it joyously celebrates the conflicting forces and feelings of a white, married couple adopting three Hispanic siblings, who drop us into an emotional pinball game where we constantly bounce between well-earned laughs and throat-clenching tears.

Director and co-writer Sean Anders based “Instant Family” on his own experience adopting three siblings.

But some of the movie's sharp comic edge should probably be credited to Mariade Green, an adoptee at 13 who served as an adviser on the set and supplied the kids' back story and the savagely perceptive insights that provide twisted laughs during several adoptive parent support-group meetings.

We first meet Pete and Ellie operating a real estate business that also flips houses.

An emo-video on an adoption website pushes them into their first meeting to explore becoming foster parents.

The group includes a woman with dreams of coaching an Olympic champ, a gay couple and a married twosome who've come because they say God told them to.

Two hilariously paired social workers, Sharon and Karen (Tig Notaro and Octavia Spencer), could almost star in their own spinoff sequel.

Straight-laced Sharon assumes a bureaucrat's demeanor, carefully crafting her diplomatic words. Karen has no filter, and zero interest in sugarcoating opinions or blunt observations.

Neither does Pete, who says stuff like, foster children should be advertised as “Rescue Kids,” like dogs and cats, so more of them would find homes.

Pete and Ellie meet and like Lizzy, who has two siblings: sensitive, vulnerable Juan (Gustavo Quiroz) and little Lita (Julianna Gamiz), who will only eat potato chips, and can go from angel to Tasmanian devil in a flash.

They get along just great. Until the “honeymoon” ends and the expected, brutal adjustment period begins.

Anders' screenplay (co-written by John Morris) sidesteps most of the usual adoption story cliches, although it brings the kids' birth mom out of prison just in time to create some conflict by contesting their pending adoptions.

Margo Martindale provides great fun as effusive, no-nonsense Grandma Sandy, paired with Julie Hagerty's quietly comic Grandma Jan.

“Instant Family” belongs to a long list of movies about middle-class families who never need to deal with financial pressures, one stark bit of realism ignored here.

Still, “Instant Family” should be commended for finally erasing the memory of John Ritter's wretched 1990 foster kid comedy, “Problem Child.”

<b>Starring:</b> Mark Wahlberg, Rose Byrne, Isabela Moner, Octavia Spencer, Margo Martindale, Tig Notaro

<b>Directed by:</b> Sean Anders

<b>Other:</b> A Paramount Pictures release. Rated PG-13 for language, drug references, sexual material. 117 minutes