Just a guy with boxes making a delivery to a New York office tower. Just a guy who walks past the security guards onto the set of a live TV show. Just a guy who pulls out a gun and forces the host to strap on a suicide vest.

That's how the taut and timely Money Monster begins, with just a guy - a seriously disgruntled guy by the name of Kyle Budwell (Jack O'Connell) - confronting Lee Gates (George Clooney), the self-described "Wizard of Wall Street" and host of the stock-tips circus act that gives the movie its name.

"Who's that guy on camera 2?" asks Lee's longtime producer, Patty Fenn (Julia Roberts), watching on a monitor as the stranger edges onto the set.

For the next 90-plus minutes, Lee and Patty get to know Kyle pretty well as their show is hijacked - and as an audience of millions tunes in to gawk at what could be a bloodbath. Whatever the outcome, one thing's for sure: The ratings are going to kill.

Directed with cool dexterity by Jodie Foster, this rage-against-the-one-percenters thriller plays like a cross between The Big Short and Network. Unfolding in real time, Money Monster is smart and gripping - at least until the third act, when everyone exits the midtown Manhattan TV studio for a march down to Wall Street and some high-tech trading hugger-mugger.

As Lee and Kyle leave the building, surrounded by NYPD hostage response cops and a horde of onlookers, a certain amount of credulity leaves the building with them.

Foster was one of the stars in a similar setup 10 years ago - in Inside Man, with Denzel Washington and Clive Owen, directed by Spike Lee. In Money Monster, the Oscar-winning actress takes her fourth turn behind the cameras, eliciting terrific work from her three leads.

Clooney's the arrogant biz-world prognosticator, mocking the CEOs, touting IPOs, and acting like a clown while he's doing so. He boogies with blinged-out chorus girls, he pounds a big red prop buzzer, but his cocky bluster turns to sniveling dread when Kyle shows up with his armaments and his angst.

O'Connell, the British actor who starred in Angelina Jolie's grueling Olympic hero/POW drama, Unbroken, plays the angry New Yorker with trip-wire palpability. Kyle invested his life's savings in stocks for a company that Lee had guaranteed as a sure thing. Then the stock tanked. Kyle wants restitution on a major scale. If he doesn't get it, Lee gets retribution instead.

Watching from the control booth, Roberts' Patty is as much in control as anyone can be, given the circumstances.

Hers is not an easy acting job: Wearing a headset, wheeling in a chair behind a bank of monitors, barking orders to the crew, Roberts doesn't get a fancy wardrobe, a dreamy romantic scene, or a rollicking action number, for that matter. With the exception of a few minutes at the front and back of Money Monster, the actress and Clooney never even share the same physical space.

But she's inside her costar's head, talking to his Lee via an earpiece that Kyle remains unaware of.

Even if Money Monster ultimately gets held hostage by its plot intricacies, Clooney, Roberts, O'Connell, and Foster do their jobs. It's a movie worth investing in.