Chapter 6, Strip: Part 1, Part 2, Part 3 Summary

In Part 1, Bletchley Park knows everything about German U-boat 653. The night Jericho and Claire spent together was the night this U-boat slipped into a French naval port. 653 joined 10 other U-boats in the patrol. It had 12 torpedoes and fired four of them. The commander messaged on March 3 that the U-boat would not return. The cryptologists could read the code up until March 9 when the Germans changed their weather codebook. It was a Shark blackout. The Allied forces could not see anything anymore.

On March 16, 653 has no heat. The only torpedo left is defective. It is time to go home. A submariner watches through the periscope. He sees a quick flash of light. It is someone lighting a cigarette. They set off the alarm. They have caught up to the Allied convoy. 653 comes out its emergency dive...