But since the situation is desperate, with the help of Seven Voyager's shields are modified to try to repel the discharges so they can approach the planet. Since trying to beam up the deuterium doesn't work,Harry Kim volunteers himself and Tom Paris to fly a modified shuttle to the surface and, wearing modified environmental suits, collect the deuterium. They find that the deut is concentrated in a viscous, freezing cold metallic fluid that's found in pools on the surface. Harry is pulled in somehow, but Tom rescues him...only to find that their suits have been compromised by the fluid; they stumble towards their shuttle (the Demon planet makes surface-to-ship communications impossible), but collapse, unconscious and running out of oxygen. Running out of alternatives and worrying about Harry and Tom, Janeway decides to land the ship--they're stuck there anyway, so might as well put them in close reach of the deuterium and Tom and Harry. After Voyager has a rough landing, Seven and Chakotay,in environmental suits, search for their comrades in a cave; Chakotay slips and falls down a steep slope toward a pool of the metallic fluid--Seven grabs an arm, but starts getting pulled down, too, until another hand--a bare hand--catches Chakotay's other arm and yanks him to safety. It's Tom Paris, and he's not in an environmental suit, giddy and thriving in the Demon planet's toxic atmosphere. Paris tells about how he and Kim (who's deeper into the cave, collecting deuterium) fell unconscious, then woke up, without the suits, feeling exhilarated. Harry and Tom are happy-- too happy, and Chakotay is concerned; Janeway has Harry and Tom beamed aboard the ship--no sooner do they do so than they start choking on Voyager's air. Investigation by the Doctor reveals that the liquid is now part of their system and has "bioformed" them--made them adapt to the planet, but now that they can breathe the planet's air, Voyager's air is now deadly to them--and the process appears to be irreversible; Tom and Harry are kept alive in sickbay, sealed off by a forcefield with some of the planet's gases. Since the planet's unique atmosphere can't be replicated...the only option would be to load up on the planet's gases before they leave, and that would only last Tom and Harry a little while. Janeway sends Seven, Chakotay and Harry back out to the planet to learn more, while B'Elanna and Janeway run tests on samples of the fluid...large amounts of which, strangely, are gathering beneath Voyager...