Flash tangles with a speedy samurai.
Daisho, a master swordsman, defeats a horde of Samuroids. At Baron Katana's command, Daisho hurls the one Samuroid corpse into the sea. Police forensic scientist, Barry Allen, and his wife, Picture News reporter, Iris West, arrive in Tokyo. Allen and West are greeted by Captain Hashi, a colleague of Allen's. Two men commandeer a fighter jet, on the airfield, and fire it's rockets at Allen, West , and Hashi. Allen, as the Flash, intercepts the rockets, moving so fast as to be invisible to the naked eye. The Flash neutralizes the invisible aura that protects him from the heat of friction, causing him to burst into flames.
The heat seeking rockets change course, locking on to the Flash's greater heat signature. The Flash leads the rockets back to the fighter jet, which is destroyed on impact. The Flash, as Allen, returns to West and Hashi, with neither even aware that he ever left their side. While Allen confers with Hashi about Baron Katana, Hashi's assistant, Tushi, shows West around the crime laboratory. Daisho raises concerns about shrimpers trolling the waters near Baron Katana's family stronghold, the Black Heron. The shrimpers haul up the dead Samuroid in their nets. Hashi is informed of the discovery.
West pulls Allen away from the investigation, insisting on a night on the town. After attending a sumo wrestling match, Allen takes West to meet his old college friend, Hideki Toshiro. Now a famed director in Japan, Toshiro is working on his latest Samurai picture. Toshiro is interested in doing some location shooting at the Black Heron, but has been unable to garner permission from the property's owner. A small police outpost, in Hokkaido, is attacked by a flying horde of Samuroids. The compliment of officers stationed there are slaughtered. Hashi is informed of the attack, believing it to be connected to the dead Samuroid found by the shrimpers.
Allen, West and Toshiro rendezvous back with Hashi. A cursory examination of the Samuroid reveals that it is not human at all, but rather a humanoid machine. It's armor is also completely impervious to gunfire. Toshiro points out the crest of the Black Heron on the armor, linking the Samuroid to the House of Kayido, and Baron Katana. Having heard enough, Allen decides to investigate on his own, as the Flash. Racing up the coastline, the Flash quickly reaches the Black Heron. His approach is picked up by Daisho. Determining the Flash's point of entry into his fortress, Baron Katana prepares a warm welcome for the Scarlet Speedster.
As the Flash prowls through the corridors of the Black Heron, he suddenly finds himself surrounded by a horde of Samuroids. Barely escaping the horde, the Flash finds himself confronted by Daisho. The two men engage in a fierce battle. Ultimately, Daisho is revealed to be a Samuroid himself, meaning he is all but impervious to harm. Baron Katana reveals himself to the Flash, as Daisho closes in for the kill. Hashi learns that Baron Katana is the landowner of the Black Heron, and prepares to head out to arrest him. When Hashi inquires as to Allen's whereabouts, West covers for him, placing her in a particularly tight spot.
West knows that Allen is already at the Black Heron, as the Flash. West fears his long absence means that the Flash is in trouble. Hashi, though, won't head to the Black Heron, and the Flash's rescue, without Allen. West is faced with the prospect of revealing Allen's identity as the Flash to Hashi and Toshiro, in order to get them to storm the Black Heron, and save the Flash's life.