At 4 a.m., it was still dark. The rest of the U-211 submarine is over. Prion glanced up at the sky, then waited for his crew to burrow back into the submarine one by one. He was used to being the last to get into the submarine in order to be able to personally inspect the hatch covers.

Soon everyone was inside the submarine, and Prion closed the hatch, and the air mixed with bad smells replaced the fresh, cold sea breeze.

"Keep diving! Depth positioning is 35 meters. After 5 minutes, save electricity and maintain course. Prion commanded loudly.

His first mate was already in place, repeating his command loudly: "Continue to exhaust the dive to a depth of 35 meters." Turn off the main lights after 5 minutes!"

The shape has become clear, and the combat mission has been declassified. Prion had told Sù's crew that the next day's mission was to enter Scapa Bay. Since the next almost all day had to be spent underwater, Prien ordered everyone to conserve air and electricity, and not to move around unless necessary.

After about five minutes, the main lighting inside the submarine was cut off, and the instruments in the submarine's control room, the slight leakage of water droplets from the pipes, and the sound of seawater squeezing the hull from all sides mixed together, giving people a creepy feeling, accompanied by the roar of the rotation of machinery to become the noise inside the boat. It was dark, with only a few instruments carrying lights, allowing the people in the submarine to blur the silhouette of the surroundings.

At 4 p.m. the next day, all the crew finished eating, the tables, chairs and utensils were arranged, and the crew's bunks were folded.

"You take a few people and go and place the explosives you brought at the bottom of the submarine. Prion sensed that the time was almost up, so he began to prepare for the first qiē before the attack.

The first mate nodded, and walked out of the command cabin with a few people with flashlights. They loaded explosives in the torpedo compartment and the power room, and several of them had very serious expressions, knowing that this mission might be really difficult.

Prian then ordered everyone to check their life jackets, and the submarine officers and men carefully tore off the fleet logo from their hats to avoid revealing their identities if they were captured.

"Damn it!" Prion knew that there was a long wait, waiting for a miracle to come, and he held his pocket watch, nervous. So he swallowed a mouthful of saliva and forced himself to compose.

"Attention everyone! We risk sinking every minute of the next minute! Everyone get ready for battle! We're heading to Scapa Bay. Our mission is very simple - to make a big fuss in Scapa Bay and avenge our old High Seas Fleet. Prien loudly announced the full order.

There was an eerie silence in the command cabin of the entire submarine, and everyone stared at their captain and commander silently, they originally thought that this was a reconnaissance mission, or a mine-laying mission, but they never thought that this time they were real.

"Revenge!" After a long time of shock, another sailor finally chimed in with a suppressed voice: "Avenge those predecessors of Operation Rainbow!"

"Yes, revenge! We want the British! who is the master of this sea!" said the first mate excitedly.

"Yes, this is what you want! Even if you die, you have to tear off a piece of flesh from the British!" Brian nodded and said, "Keep course!"

As the minutes ticked by, everyone waited for the moment when they could act. It's like a bride waiting for a sedan chair, full of joy and anticipation, but extremely nervous and nervous.

"Periscope height!" I don't know how long it took for Prien to finally open his mouth and order. He put his face on the periscope, raised the only device that could observe water targets under water, and took a closer look at the surroundings.

"This strait can't be navigated in a submersible state, otherwise it will hit those sunken ships. He looked at the surrounding scenery and compared the nautical map with the first mate, which was densely marked with the location of many sunken ships, which was an accurate map completed by German merchant ships and spies for many years.

"What then, shall we go up?" the first mate asked in disbelief, looking at his commander in surprise.

"Float!" Prien said, nodding.

At 7 p.m., Prion gritted his teeth and finally gave the order for the submarine to begin to float. The electric motor began to run at full speed and traveled at a depth of about 25 meters for another half hour, until the underwater listener provided by the sonar soldier reported that no noise was heard from the surface of the sea, and Prien once again observed the situation with a periscope.

He felt that he had not been so cautious and nervous in several years, and upon ascending to a depth of 5 meters, Prien ordered the periscope to be raised again. After observation, night had fallen and the sea was in good condition. At 7:15, Prion finally made up his mind and gave the order to surface.

The submarine's airtight water tank squeezed all the seawater out of the submarine, and the behemoth, which was close to 1,000 tons, finally surfaced. Under the cover of night, the U-211 submarine sailed almost close to the shoreline.

Because of the air source, the diesel engine on the submarine began to run. For the next two hours, the U-211 was very powerful, sailing at almost full speed with the tide northwest of the Helm Strait.

But at 9 p.m., they were in trouble. A British freighter appeared on their course, and the U-211 submarine scrambled to make an emergency dive. Finally, a minute before being discovered, he dived below the surface of the sea.

In order to avoid passing ships on the surface, submarines often dived into the water and had to contend with the increasingly strong currents. The timing of entry into Scapa Bay is somewhat skewed, and there is a strong tidal wave flowing into Scapa Bay at this time. Like a canoe falling into a rapid, U-211 barely managed to enter the Cork Strait at night.

At 23:31, the submarine began to enter Scarpa Bay, during which the bottom of the hull even collided with the mooring laid on the seabed, causing the submarine to turn sharply to the right and run aground. U-211 was successfully refloated by Prien because he had previously ordered the submarine to travel in a semi-submersible state according to the depth of the water, and now it had to continue to vent into the tank.

The strait ahead gradually widened, and the current slowed down. In order to protect against submarine attacks, the underwater area of the strait, which is less than a kilometer wide, is densely covered with many artificial shipwrecks and other underwater obstacles. According to information gathered prior to departure, access to Scarpa Bay by route through the Guò Coke Strait is extremely difficult, almost impossible to penetrate. At this time, the U-211 submarine was sailing along this route.

At 12:27 a.m., Prion finally confirmed a result. They have entered Scapa Bay. But just when everyone breathed a sigh of relief, the most devastating thing happened. Suddenly, a bright light shone towards U-211, illuminating the enclosure of its conning tower.

Prien, who was observing from the conning tower, was stunned by the scene in front of him, and he was even desperately prepared. The light came from the headlights of a taxi that happened to pass by on the highway in the small town of Saint-Marie on the shore. Under the bright light, Prion and the first mate on the control tower could even see the trucks and sentry posts used by the British Royal Navy officers and sailors on the shore.

Everyone panicked, and it looked like their whereabouts had been exposed, and an attack was inevitable. The first mate's hand was already pressed on the pistol holster at his waist, and Prion on the side had even pulled out his P-38 pistol.

But everyone knows that not to mention relying on these short guns in their hands, even if you count the 88mm cannon in the bow and the 40mm anti-aircraft gun in the stern, they have no chance of winning. Holding his breath, Prion could even see two soldiers from the British sentry lighting cigarettes at each other, and perhaps the two men would fire a warning shot in the next second, so that Prien would cut off the last glimmer of hope.

This time it seemed that God had chosen to side with the Germans, and what Prien feared never came. Luckily, the taxi didn't spot the submarine and turned around and continued toward Scapa Bay.

"If I do this again, I'm going to be scared to death here. The first mate leaned against the shell of the submarine's conning tower and gasped, his hands still shaking.

For a few seconds, he even admired Prien, who was silent, and felt that the commander was extremely calm. However, this worship did not last long, for the first mate looked down and saw his captain stuffing his P-38 pistol into the holster with trembling hands, and he failed twice in a row to get the pistol back.

"Be careful, we need to find the best position to attack, we only have one chance, and since we're here, we're going to make a big fuss at a time." Prien recovered for a moment before he spoke.

The first mate nodded, and the two men picked up their binoculars and began to continue to monitor the situation around them. In any case, there is no way back for the shape in front of him. The U-211 submarine is currently tasked with finding targets for attack. Prien took a closer look at the surface of the sea while directing the submarine to continue westward sailing.

As darkness hung over the British Isles, the entire Royal Navy was devastated by the debacle off the coast of the Netherlands. At the behest of Admiral Winston Churchill, the King had ordered more warships to be called up to counter the German naval threat.

So in Scarpa Flow, almost all of the naval aircraft carrier forces that the British Navy could handle. With the newly launched aircraft carrier HMS Ark Royal, HMS Glorious and sister ship INS Brave, as well as the aging aircraft carrier USS Athletic, Churchill intended to cover the battleship raid on the Wilhelmshaven with an equal number of aircraft carriers, and wipe out the German High Seas Fleet in one fell swoop.