In the early hours of the morning, Rear Admiral Hipper leads the German battlecruiser squadron out of port. They set sail for the east coast of England, where they are to attack coastal targets. The British navy knows they are coming, thanks to the work of Admiralty code breakers. A British force is also putting to sea, intent on blocking the German battlecruisers return to port and forcing a battle in which they will be destroyed.
The British do not realise that they are sailing into terrible danger. The Germans are sending their battlecruisers to bombard coastal targets, but unbeknownst to the British they are also sending the rest of their fleet in support. If the two sides meet, it is the British who will be defeated, an outcome that would completely change the naval balance in the North Sea.