Chernobyl Tour had a small, battery-operated camera perched by the checkpoint into the zone that Yemelianenko and Aslamova could remotely access. It was there to monitor their booth. But the day of the invasion, they said, it provided early information about Russia’s movement of troops through Belarus and past Chernobyl as Moscow began its attempt to take Kyiv.

“The first thing that the Russians did when they passed the checkpoint of Chernobyl was taking off the Ukrainian flag and shutting off all the cameras,” Aslamova said.

But they missed the little camera at the booth, which kept rolling. So the tour operators started to count the number and type of military vehicles. One hundred. Five hundred. It kept going. Yemelianenko said he passed that information to contacts at Ukraine’s military and intelligence agency. The Kyiv-based tour guides also contacted the company’s network of employees in villages around Chernobyl who were coming under Russian occupation.

Within a day, Chernobyl Tour had transformed into a sort of Ukrainian network of informants tracking Russian troop movements. Its employees were part of something that became key to Ukraine’s resilience: the will of everyday people to take the defense of their nation into their own hands.