〃About three months。〃
〃Was that a long time to look for a lost station？〃
In the main room； Renshaw shrugged。 〃It was longer than usual。 Why？〃
Schofield came back in through the doorway。 He was carrying some metal objects in his hands。
〃I think our boys were doing some things down here that they weren't supposed to；〃 Schofield said； smiling。
He held up a piece of white cord。 It looked to Renshaw like string that had been covered over with white powder。
〃Detonator cord；〃 Schofield said as he tied the white powdery cord in a loop around his wrist。 〃It's used as a fuse for close…quarter explosives。 That powdery stuff you see on it； that's magnesium…sulfide。 Magnesium…based detonator cords burn hot and fast…in fact； they burn so hot that they can cut clean through metal。 It's good stuff； we sometimes use it today。
〃And see this。〃 Schofield held up a rusted pressurized canister。 〃VX poison gas。 And this〃…he held up another tube… 〃sarin。〃
〃Sarin gas？〃 Renshaw said。 Even he knew what that was。 Sarin gas was a chemical weapon。 Renshaw recalled an incident in Japan in 1995 when a terrorist group had detonated a canister of sarin gas inside the Tokyo subway。 Panic ensued。 Several people were killed。 〃They had that stuff in the sixties？〃 he asked。
〃Oh； yes。〃
〃So you think this station was a chemical weapons facility？〃 Renshaw asked。
〃I think so； yes。〃
〃But why？ Why test chemical weapons in Antarctica？〃
〃Two reasons；〃 Schofield said。 〃One： Back home； we keep nearly all of our poison gas weapons in freezer storage； because most poison gases lose their toxicity at higher temperatures。 So it makes sense to do your testing in a place that's cold all year round。〃
〃And the second reason？〃
〃The second reason is a lot simpler；〃 Schofield said； smiling at Renshaw。 〃Nobody's looking。〃
Schofield headed back into the next room。 〃In any case；〃 he said as he disappeared behind the doorway； 〃none of that's really much use to us right now。 But they do have something else back here that might be helpful。 In fact； I think it might just get us back in the game。〃
〃What is it？〃
〃This；〃 Schofield said as he reappeared in the doorway and pulled a dusty scuba tank out into view。
Schofield set to work calibrating the thirty…year…old scuba gear。 Renshaw was tasked with cleaning out the breathing apparatus…the mouthpieces； the valves； the air hoses。
The pressed air mix was the main risk。 After thirty years of storage； there was a risk that it had gone toxic。
There was only one way to find out。
Schofield tested it…he took a deep inhalation and looked at Renshaw。 When he didn't drop dead； he declared the air OK。
The two men worked on the scuba gear for about twenty minutes。 Then； as they were nearing readiness； Renshaw said quietly； 〃Did you ever get to see Bernie Olson's body？〃
Schofield looked over at Renshaw。 The little scientist was bent over a pair of mouthpieces； washing them out with seawater。
〃As a matter of fact； I did；〃 Schofield said softly。
〃What did you see？〃 Renshaw said； interested。
Schofield hesitated。 〃Mr。 Olson had bitten his own tongue off。〃
〃Hmmm。〃
〃His jaw was also locked rigidly in place and his eyes were heavily inflamed…red…rimmed； bloodshot。〃
Renshaw nodded。 〃And what were you told happened to him？〃
〃Sarah Hensleigh told me you stabbed him in the neck with a hypodermic needle and injected liquid drain cleaner into his bloodstream。〃
Renshaw nodded sagely。 〃I see。 Lieutenant； could you have a look at this please？〃 Renshaw pulled a waterlogged book from the breast pocket of his parka。 It was the thick book that he had taken from his room when they had evacuated the station。
Renshaw handed it to Schofield。 Biotoxicology and Toxin…Related Illnesses。
Renshaw said； 〃Lieutenant； when someone poisons you with drain cleaner； the poison stops your heart； just like that。 There's no struggle。 There's no fight。 You just die。 Chapter 2。〃
Schofield flipped the water…soaked pages to chapter 2。 He saw the heading： 〃Toxin…Related Instantaneous Physiological Death。〃
He saw a list of what the author had called 〃Known Poisons。〃 In the middle of the list； Schofield saw 〃industrial cleaning fluids； insecticides。〃
〃The point is；〃 Renshaw said； 〃there are no outward signs of death by such a poison。 Your heart stops； your body just stops。〃 Renshaw held up his finger。 〃But not so certain other toxins；〃 he said。 〃Like； for instance； sea snake venom。〃
〃Sea snake venom？〃 Schofield said。
〃Chapter 9；〃 Renshaw said。
Schofield found it。 〃Naturally Occurring Toxins…Sea Fauna。〃
〃Look up sea snakes；〃 Renshaw said。
Schofield did。 He found the heading： 〃Sea Snakes…Toxins； Symptoms and Treatment。〃
〃Read it；〃 Renshaw said。
Schofield did。
〃Out loud；〃 Renshaw said。
Schofield read； 〃The mon sea snake （Enhydrina schis…tosa） has a venom with a toxicity level three times that of the king cobra； the most lethal land…based snake。 One drop （0。03 mL） is enough to kill three men。 mon symptoms of sea snake envenomation include aching and stiffness of muscles； thickening of the tongue； paralysis； visual loss； severe inflammation of the eye area and dilation of the pupils； and； most notably of all； lockjaw。 Indeed； so severe is lockjaw in such cases； that it is not unknown for victims of sea snake envenomation to…〃
Schofield cut himself off。
〃Read it；〃 Renshaw said softly。
〃…to sever their own tongues with their teeth。〃 Schofield looked up at Renshaw。
Renshaw cocked his head。 〃Do I look like a killer to you； Lieutenant？〃
〃Who's to say you didn't put sea snake venom inside that hypodermic syringe？〃 Schofield countered。
〃Lieutenant；〃 Renshaw said； 〃at Wilkes Ice Station； sea snake venoms are kept in the Biotoxins Lab； which is always…always…locked。 Only a few people have access to that room； and I'm not one of them。〃
Schofield remembered the Biotoxins Laboratory on B…deck； remembered the distinctive three…circled biohazard sign pasted across its door。
Strangely； though； he also found himself remembering something else。
He remembered Sarah Hensleigh telling him earlier： 〃Before all this happened； I was working with Ben Austin in the Bio Lab on B…deck。 He was doing work on a new antivenom for Entrydrina schistosa。〃
Schofield shook the thought away。
No。 Not possible。
He turned to Renshaw。 〃So who do you think killed Bernie Olson？〃
〃Why； someone who had access to the Biotoxins Lab； of course；〃 Renshaw said。 〃That could mean only Ben Austin； Harry Cox； or Sarah Hensleigh。〃
Sarah Hensleigh。。：。
Schofield said； 〃Why would any of them want to kill Olson？〃
〃I have no idea；〃 Renshaw said。 〃No idea。〃
〃So as far as you know； not one of those people had a motive to kill Olson？〃
〃That's right。〃
〃But you had a motive；〃 Schofield said。 〃Olson was stealing your research。〃
〃Which kind of makes me the ideal person to set up； doesn't it？〃 Renshaw said。
Schofield said； 〃But if someone really wanted to set you up； they would have actually used drain cleaner to kill Olson。 Why go to the trouble of using sea snake venom？〃
〃Good point；〃 Renshaw said。 〃Good point。 But if you read that book； you'll find that drain cleaner has a 59％ mortality rate。 Sea snake venom has a 98 ％ mortality rate。 Whoever killed Olson wanted to make sure that he died。 That's why they used the sea snake venom。 They did not want him to be resuscitated。〃
Schofield pursed his lips in thought。
Then he said； 'Tell me about Sarah Hensleigh。〃
〃What about her？〃
〃Do you two get along？ Do you like her； does she like you？〃
〃No； no； and no。〃
Schofield said； 〃Why don't you like her？〃
〃You really want to know？〃 Renshaw sighed deeply。 He looked away。 〃It's because she married my best friend…actually； he was also my boss…and she didn't love him。〃
〃Who was that？〃 Schofield asked。
〃A guy named Brian Hensleigh。 He was head of geophysics at Harvard before he died。〃
Schofield remembered Kirsty telling him about her father before。 How he had taught her advanced math。 And how he had died only recently。
〃He died in a car accident； didn't he？〃
〃That's right；〃 Rensha