'Iceberg', written by David Banks, features the Seventh Doctor, Ace and Bernice.
Back Cover Blurb
'Depends on how you define alien,' the Doctor said simply. 'They were human once.'
In 2006 the world is about to be overwhelmed by a disaster that might destroy human civilization: the inversion of the Earth's magnetic field. Deep in an Antarctic base, the FLIPback team is frantically devising a system to reverse the change in polarity.
Above them, the SS Elysium carries its jet-set passengers on the ultimate cruise. On board is Ruby Duvall, a journalist sent to record the FLIPback moment. Instead she finds a man called the Doctor, who is locked out of the strange green box he says is merely a part of his time machine. And she finds old enemies of the Doctor: silver giants at work beneath the ice.