The invaders had not returned. Not yet. But along about 600 miles of Ukraine’s northeastern border territory that The New York Times visited late last year and again in the early spring, the war has never left.

Much of this area, in the Kharkiv and Sumy regions, was farmland once. Now a farmhouse hosted a counter-saboteur unit — made up of anti-Putin Russians, to avoid sending Ukrainian troops into Russia — preparing before dawn for a cross-border raid.

The fields are far too exposed to Russian fire for anyone to try a harvest. Instead, they are sown with “dragons’ teeth,” concrete antitank barriers typically bound together with cables and threaded with razor wire.

In 2022, Russian troops rolled over this area and almost to the doorstep of major cities like Kharkiv and Sumy. Then, before the end of that year, Ukrainian forces pushed them back across the border.