Spring 1855, the height of the Crimean War, and the siege of the Russian city of Sebastopol continues. In a desperate attempt to cut the Russians' supply line at the Sea of Azoff, the Allies commit 15,000 troops, five batteries of artillery, and virtually every ship of their Black Sea fleets. Commander Phillip Hazard and HMS Huntress undertake the crucial mission of marking a new channel for the Allies' attack under the formidable shore batteries guarding the Straight of Yenikale.