The “What happened to my daughter?” mystery “Searching” is like a poker game. Everything goes well until that last hand where you lose it all.

And leaving the table, you have the sneaking suspicion that the other guy cheated you.

John Cho may not be the most compelling lead, not giving us that rising sense of panic that is the normal human reaction to the shocking realization that your kid is missing, that you don’t know enough about her, her friends or her online profile to help the cops find her.

“I KNOW my daughter!” is played more “I uh, know my daughter.”

And Debra Messing may be the most helpful cop in the Western Hemisphere, a real Janey on the spot, always available, too patient when talking Dad through the sorts of scenarios and the sorts of places he can do that will help her to help him.

The “ticking clock” urgency of this search, its desperation, is missing. Filling the screen with hyped “missing teen” coverage is no substitute for fear and dread that the cop should impart or the fear and panic somewhat muted in Cho’s performance.

But the plot, the actual nuts and bolts of how you dissect a loved one’s digital life — phone to laptop to social media sites, search histories, etc. — is damned fascinating, a blend of “Lion,” the movie about an Indian orphan who finds his mother via Google Earth, and “Unfriended,” the Facebook murders movies.

The computer forensics that this digital “infrastructure management” consultant carries out is within the capabilities of any parent. And kids? We’re taking notes.

Margot (Michelle La) is a cute kid, 16, a gifted pianist and her daddy’s pride and joy. But in the opening montage we’ve seen, via their online posts, calendar, videos and photos, that he’s raising her alone. Mom (Sara Sohn) died just a couple of years ago.

Margot is carrying on, Dad seems utterly deflated by their loss.

Then one night, Margot tells him she’s pulling an all-nighter with her study group, and she doesn’t come home. She tried to call, Facetime, the works. But Dad slept through it.

And once he gets past the fifth “Young lady, you are in SO much trouble” text, he panics.  That’s when he calls the cops.

Det. Vick (Messing) is the one who sends David searching his kid’s laptop, looking at “Shedding light on who your daughter is, and who she talks to…I need to know a lot more about her.”

Thus begins David’s journey, getting around Facebook and Instagram passwords, discovering her “Youcast” (vlogging) presence, calling everybody on her “friends” list to try and track her movements.

“Friends” on Facebook, as if he didn’t know it, isn’t like “real” friends. One of the most biting messages of this film from director/co-writer (with Sev Ohanian) Aneesh Chaganty is the isolation of the digital age. Margot “knows” people, but connects with no one.

And David, aside from his younger brother (Joseph Lee), is just as bad.

People that lonely are ripe for catfishing, vulnerable to anybody who might pay attention to them, even online. When a story like this breaks, it can become a regional if not national phenomenon. And online comments on your tragedy aren’t always kind.

The script throws several plausible possibilities at us for a solution, and yanks us about in the best manipulative mystery-thriller tradition.

And then the payoff comes, and it’s the least plausible, the “How’d you draw to an inside straight?” last hand of poker you lose it all over.

It’s cool to see Cho (“Star Trek/Harold and Kumar”) get this sort of break, even if he’s not the most compelling parent — his meltdowns seem like pulled punches. There are a couple of great “Who I really am” jokes commenting on the difference between our online identity and how uncool we actually are.

There’s one sizzling “Could THIS be what happened” red herring. And the “Unfriended” way of making the screen — filled with Skype, Facebook, Google Search, and Google Maps searches — a character as well as a plot device is riveting.

Who hasn’t freaked out when “buffering” came up on their phone, notebook or PC screen at the worst possible moment?

But the end is too much like a “You may have already won” come-on, a poker game where the other player is using a 56 card deck, when you’re still counting on 52.

A cheat, in other words.

MPAA Rating: PG-13 for thematic content, some drug and sexual references, and for language

Cast: John Cho, Debra Messing, Michelle La, Sara Sohn

Credits:Directed by Aneesh Chaganty, script by Aneesh Chaganty, Sev Ohanian. A Screen Gems release.

Running time: 1:42