While Valhalla Sector prepares to exchange Markus and Erin for Meaghan, Lee Chen and Kurdy convince a group of dubious Thunder Mountain volunteers to undertake a mission to attack Valhalla Sector. Although they do not trust Lee, the group has faith in Kurdy and agrees to the mission.

The leaders take Devon prisoner and place him in the cell next to Jeremiah. Father and son know the leaders are exchanging Markus and Erin but they cannot imagine what Thunder Mountain is offering in exchange, except that it must provide a key to the Big Death.

When the exchange takes place, Markus sees Meaghan but is unable to stop her from carrying out her part in the drama. Meanwhile, the Thunder Mountain forces launch their attack on Valhalla Sector. Mister Smith makes his way to the battle just in time to save Kurdy from a sleeper agent within the attack team. The Valhalla Sector leaders return to the base and lock it down with Jeremiah, Devon, Libby and Meaghan inside. As Meaghan spreads the Big Death through Valhalla Sector, Libby's quick thinking provides a way for Jeremiah and Devon to try attempt survival amidst the turmoil.