Four bladesmiths are in for a workout when they are tasked with forging signature blades from gym equipment. The competitors flex their skills, battling forge welding failures and warps. After a severe round of testing, the two remaining smiths have only four days in their home forges to recreate one of Japan's deadliest swords: the Nagamaki.

Four bladesmiths fight fire with fire when they must dismantle a forge and use that steel to construct a blade. The competition gets heated as the smiths struggle to salvage enough material to create a san mai billet, leading one competitor to crack under the pressure. After a punishing round of tests, the final two return to their home forges where they have just four days to recreate one of history's most elegant weapons of war: The Partizan.