There’s a battle raging in the streets around you.

Two passionate factions are fighting for control of the planet — and the grandstand at the State Fair.

In a contest that mixes geocaching with a high-tech version of capture the flag, “agents” armed with Android smartphones are locked in a 24/7 struggle to dominate some of our most cherished landmarks: “Spoonbridge and Cherry,” the Landmark Center in St. Paul, Snoopy statues everywhere.

It’s a mission so compelling that hundreds of people in the Twin Cities — many of them IT workers — give up their lunch hours, evenings and weekends in an attempt to take over the virtual landscape of the augmented-reality game Ingress.

Like many video games, Ingress is wildly popular, with more than 2 million agents in 132 countries. It has a complicated, continuously evolving back story and a language all its own.

But hiding behind the keyboard isn’t an option. This game demands that its players get up, get out and explore.

Claim a portal for the Enlightened team, turn it green on the smartphone screen. Or join the Resistance team, and make landmarks glow blue online. But above all, be social and have fun.

That’s what a dozen or so Enlightened players did on a recent Friday evening.

“We could go turn the Sculpture Garden green, or we could go bust up Uptown,” said Samantha Karsten, plotting over pregame beers and dinner at Brit’s Pub in downtown Minneapolis.

Most of the players at the table met each other through the game, learning screen names before real names.

Phones fully charged, auxiliary batteries in tow, they start walking to the Minneapolis Sculpture Garden, eyes glued to their phones, tapping their screens to play along the way.

“Look for blue,” Rachel Christianson said. “Blow it up!”

Luring gamers outside

The green-vs.-blue battle is Ingress at its most basic.

When Niantic Labs, a start-up within Google, launched the free game in 2012, it came with an elaborate science fiction back story. The tale is still unfolding through weekly YouTube videos contemplating a substance called “exotic matter” that spills out of the portals and an alien force known as “Shapers.” Play on the ground affects how the plot unfolds, with the Enlightened helping the Shapers and the Resistance, well, resisting.

But the overall goal is more ambitious than a game: Use technology to lure people out to explore the world around them. Players have to be near portals to attack them and collect keys to link far-flung landmarks together.

“So much tech pulls you into these online networks, and games in particular really suck you into an alternative reality,” said John Hanke, a Google vice president and founder of Niantic. “Ingress is a reason for people to get together.”

Operations can be local, with one person claiming and linking portals in his or her neighborhood, or global, with elaborate plans drawn up by international players chatting within the game and through Google Hangouts.

Hanke said the social aspect of Ingress “has been shocking, frankly.”

“We thought folks would play with people they already knew,” he said.

‘Very meaningful’

Stacy Blasiola, a Resistance player and a doctoral student at the University of Illinois at Chicago, has been researching the social dynamics of Ingress.

“It’s very common to run into other players that play the game or get pulled into these online communities where you’re making plans for events in the game,” she said. “It’s very meaningful for a lot of people. You can see why, because of the relationships that are formed and the global nature of the game.”

In Minnesota, members of the Enlightened and Resistance factions chat online constantly. They work stops at portals into their daily routines, roam during lunch hours — downtown Minneapolis is a hot spot — and arrange outings to other parts of town with lots of portals, like the State Fairgrounds.

Jennifer Parks, a local Resistance player, said she keeps in daily contact with her teammates as she scouts out the portals around her.

“I have been seeing things I’ve never seen before, even though I may have driven by it a hundred times,” she said. “Sometimes even if I’m going to be standing around waiting for somebody, say meeting somebody for dinner, I’ll purposely show up early and see if there are portals nearby.”

Encouraging exploration? Goal achieved.

Friendly rivals

As the Enlightened group plays, conversation flows seamlessly between the physical and digital world, some talking, some messaging via Google Hangout.

Granted, the vocabulary sounds bizarre to the uninitiated: resonators and bursters are just some of the virtual equipment that players accumulate by “hacking” portals.

“Should we fill it up with very rare shields?”

“I got a link amp, rock on!”

“Who dumped all these keys?”

Not long after the crew begins to conquer the Sculpture Garden, they notice on screen that a Resistance opponent is tailing them, undoing their digital handiwork. They debate revealing themselves to the pursuer — a mischievous but good-humored opponent they’ve crossed paths with before.

A few minutes later, the “smurf” (slang for Resistance player) is surrounded by Enlightened players — also known as Kermits or frogs (because of the green) or bulbs (a play on light bulbs). Many of the Enlightened players that night wore green clothing or blinking green buttons to show their allegiance.

But smurf Jon Schultz of Edina isn’t fazed. Another member of the Resistance dispatched him to downtown after noticing via online map that there was a high-level Enlightened contingent turning landmarks green.

“I could see at least eight [Enlightened players],” said Schultz, who followed the trail to the Sculpture Garden and started blowing up the green portals.

But his attack was lighthearted, and he didn’t mind bumping into his opponents.

“It’s fun to meet the people behind the names,” he said.

Still, he knew better than to let his guard down.

Even while the players were exchanging pleasant small talk, they were tapping their Android screens: The battle for the surrounding sculptures — ahem, portals — raged on.