The divers were shocked to the moment they opened the hatch. It was September 1939. A British

submarine called the Thetus had sunk near Liverpool. Now the divers had to remove the 99 bodies

inside for burial. The divers expected a heart-rending scene, and it was, colleagues, comrades, all dead.

But they did not expect to find many of the men inside naked or nearly so, their clothes and tatters.

Why had they shredded their own uniforms?

And the mysteries only deepened from there.

Some sailors had nearly bitten their own tongues off. What could cause

such agitation? The Thetus was also stocked with emergency underwater breathing devices,

and most of the devices were found in perfect working order. So why hadn't more men used them to

escape? Plus, from what the survivors said, the British Navy knew a few people had died inside the

sub's escape chambers, the water locks that let them exit the sub without flooding the rest

of it.

Several sailors had entered the locks with the underwater breathing devices, only to tear

the devices off their face and drown.

Why would they do that? What had gone so wrong? Solving these mysteries could save other sailors in the future, so the British Navy turned

to the best man they could think of, JBS Halldane, also known as Jack. Haldane was a tall,

scowling biologist with a bald head and push-brew

mustache. He was not exactly popular. One colleague said he had a persecution complex and a chip on

both shoulders. But the Navy tapped Hall Dane anyway. Probing the Thetis mysteries would be

dangerous in the extreme, and

Haldane loved dangerous science. Indeed, he often ran reckless experiments on himself. And just

as the Navy expected to figure out what went wrong in the Thetus and save future lives,

...