In a rare glimpse into the heart of conflict, the BBC gains access to a specialist drone unit, known as Peaky Blinders, defending Slovyansk - one of four fortress cities in eastern Ukraine's Donetsk region. Under constant bombardment from Russian drones, missiles, and glide bombs, this city is a battleground in the ongoing struggle between Ukraine and Russia. The unit members, Tetiana and Yasha, navigate the city's devastated streets on foot, armed with shotguns and relying on military intelligence to evade Russian air attacks.

Russia has been pushing for Ukraine to relinquish control of these fortress cities as part of potential peace talks resumed after nine months in Abu Dhabi. Ukrainians fear that conceding these cities would provide a strategic advantage to Russia, potentially enabling them to advance further west, including towards the capital Kyiv. Despite the ongoing danger and destruction, many residents remain defiant, unwilling to abandon their homes.

Slovyansk, once a bustling city of over 200,000 people, is now a shadow of its former self, with very few buildings left unscathed. The few functioning shops are boarded up, and the population continues to dwindle under the constant threat of air raids. Amidst the devastation, signs of resilience persist - Iryna, working in one of the city's last coffee shops, refuses to leave Slovyansk, declaring it her home. Inga, 53, also born and raised in the city, continues to work despite the danger, driven by a fear of the unknown and a lack of other viable options.

The Omega National Guard Special Forces drone unit, first encountered by the BBC two years ago in the Kharkiv region, has seen significant losses since then. The unit's leader, Oleksandr, who lost his brother in combat, describes his surviving team as a family. Despite the heavy toll of the conflict, they continue their mission to protect Slovyansk and the other fortress cities from Russian advances. The future of these cities and the region remains uncertain, with peace talks ongoing but prospects for resolution unclear.