What is the main conflict in Enigma by Robert Harris?

Tom must focus on his job as a cryptologist, or one who cracks codes for the British navy. He resides in Bletchley Park, the government communication headquarters. He works in Hut 8, trying to crack the notorious Shark code. The pressure is on Jericho. He almost cannot handle it. The first time he broke the code, he had a breakdown. This is time he is near a breakdown because he has not slept in days and has fallen ill. Still, Jericho continues on, working hard to crack Shark once more.