Explosion! Knot Buster!.Ijyuuin and Tanigawa see a Balloon-Type Heterodyne overhead while having a day off at an onsen. It appears to be heading towards a dam and hydro-electric plant. Dai-Guard is flown to the site in parts and assembled, but it is too slow and cumbersome in the mountains and cannot capture the Heterodyne. The process is repeated 3 times without success until a final effort is made using a newly delivered weapon, the Knot Buster, designed by Rika Domeki. Attached to Dai-Guard’s arm the weapon pierces and destroys the Heterodyne, however as the army paid cash for the weapon, under Shirota’s orders they take it into their possession.