On a foggy morning a few months ago, Valentyn Dmytrovych Yermolenko, an aging Ukrainian fisherman with a bad back and horrible knees, puttered down a narrow channel off the Dnipro River, his inflatable dinghy cutting through the mist.
His city, Kherson, had been taken over by the Russian Army, and on the floor of his boat, concealed under a fishing net in a black plastic tub, Mr. Yermolenko had hidden three disassembled automatic rifles.
As he took a bend in the river, he recalled, a Russian patrol boat materialized in front of him. A commander standing on the deck in crisp camouflage barked: “Grandpa! Where are you going?”
After Mr. Yermolenko muttered something about getting fish for his wife, the commander ordered a search of the boat. A young soldier stomped aboard and went straight to the black plastic tub.
“What is this?” he asked.
Mr. Yermolenko, 64, said he was so scared that he wet his pants.
Kherson, at the mouth of the Dnipro, near the Black Sea, was captured in the war’s first days. Russian officials soon declared it part of Russia forever.
Kherson’s occupation government, run by Russian military commanders and Ukrainian collaborators, wasted little time pulling down Ukrainian flags, taking over Ukrainian schools, trucking in crates of Russian rubles, even importing Russian families. Perhaps nowhere else in Ukraine did Russia’s leader, Vladimir V. Putin, devote so much money and violence, the carrot and the stick, to bend a city to his imperial will.
But it did not work.
Guided by contacts in the Ukrainian security services, an assembly of ordinary citizens formed themselves into a grass-roots resistance movement. In dozens of interviews, residents and Ukrainian officials described how retirees like Mr. Yermolenko — along with students, mechanics, grandmothers, and even a wealthy couple who were fixing up their yacht and got trapped in the city for the better part of a year — became spirited partisans for the Kherson underground.