The Doctor and Clara in a failed attempt to land in Las Vegas, land in a Russian submarine in 1983 and are left behind by the TARDIS. To the Doctor’s surprise, he finds an Ice Warrior, the famed Grand Marshal Skaldak, who had been thawed out of the ice after 5000 years. However, Captain Zhukov is distrustful of both the Doctor and Clara and has Skaldak chained up to prevent further damage to the submarine. This only proves to be a problem as by Martian Law, Skaldak now considers that humanity as a whole has declared war on the Ice Warriors. The Doctor tries to convince Skaldak that he and Clara are peaceful; however, when Skaldak believes no other Ice Warriors are left, he commits the greatest act of dishonor and exits his Armour to begin forensic analysis of human bodies. Skaldak tricks Lieutenant Stepashin into revealing the circumstances of the Cold War, and prepares to start an alternate timeline by firing off a single nuclear missile. However, Clara manages to convince him that it would be wrong to end innocent lives, just as an Ice Warrior ship arrives and retrieves Skaldak. Out of danger, the Doctor’s sonic screwdriver tells him the HADS (Hostile Action Displacement System) had been activated and sent the TARDIS to the South Pole.