Episode 4

As Iranian forces take control of the British-flagged oil tanker Stena Impero and hold the crew hostage, HMS Duncan is ordered to the Persian Gulf. The captain is briefed by the captain of the Montrose - another Royal Navy ship in the region - who comes on board for a private intelligence update on Iran. After arriving in the Gulf, the Duncan escorts a tanker through the Strait of Hormuz, while Iranian forces immediately make a move and try to capture another ship, resulting in a tense stand-off.