In 1929, Lord Barset's expedition to the Antarctic is lost without trace. Nearly a century later, his grandson returns to discover what happened to the original expedition. Instead he finds a police box frozen in ice millennia old. But something else lies here from an era before humankind, frozen in time.
The lost expedition of Lord Barset seems to be the one depicted in the AudioVisuals story Endurance, which failed due to an altercation with the Silurians. In this story, his grandson searches for signs of Silurians, but instead discovers an unrelated problem with the Ice Warriors.
This is the first use of the Ice Warriors in a Big Finish Doctor Who play since 2000's Red Dawn, apart from a brief appearance in Bang-Bang-a-Boom!
The Ice Warriors Sonic Cannon was first used in the 1968 Second Doctor story The Ice Warriors.