While Joe is practicing his swordsmanship with Ahim and Doc watching, they are notified of yet another Zangyack invasion. After Gokaioh takes out the Zugormin with the Dekaranger and Magiranger Keys, Captain Marvelous gets a clue from Navi to beware of a "sa-mu-r-ai". While they think on the clue, the Gokai Galleon crew find a kendo class at a park with Joe remembering his days in the Zangyack forces military and his senior Sid Bamick. Then, all of a sudden, a group of Kuroko with white banners appear and the Gokaigers are introduced to Kaoru Shiba, who demands the Shinkenger Ranger Keys from them. After Captain Marvelous refuses, she grabs her Shinkenmaru katana and attacks him. He dodges her attacks and is about to pull his Gokai Gun on her, but Ahim intervenes and tells him not to shoot Kaoru while Doc tells him she might know the secret to unlocking the Great Power of the Shinkenger keys. Joe then steps in and issues a challenge to the female samurai. Meanwhile, after making a fuss of the latest defeat, Warz Gill is paid a visit by his father's bodyguard Deratsueiger, whose presence makes him confident to the point of personally overseeing the intermediate attack. The duel between Joe and Kaoru is interrupted by a Zangyack invasion as the latter cuts down every Gormin Sailor on her path, before a Zangyack army led by Warz Gill, Barizorg, and Deratsueiger beams down to the scene. Warz Gill demands everyone to bow before him as the Gokaigers arrive to actively defy him. The Gokaigers eliminate the Gormin Sailors and Zugormin units, but are unable to harm Deratsueiger with the powers of the Zyurangers and Dynamen. Deciding to go after Warz Gill, the Gokaigers change into the Gingamen to hold Deratsueiger while Gokai Blue (as Ginga Blue) charges toward the Zangyack forces leader. However, Barizorg forces him to change back into Gokai Blue form and a sword fight ensues before Gokai Blue recognizes Barizorg's fighting stance as that of Sid's. After being pummeled by Barizorg's attack, Joe asks him if he is Sid; in response, Barizorg does not know him. Warz Gill then reveals to Joe that the Sid he knew was converted into the cyborg Barizorg for treason as his swordsmanship was too valuable to waste. Joe stands in disbelief as Barizorg approaches him to slash him, but Gokai Red rushes to block the attack - receiving the blow to the back. With the last of his strength before passing out, Captain Marvelous then fires at Barizorg, throwing his sword out of his hand with a stray shot hitting Warz Gill's left arm, forcing Barizorg and Deratsueiger to retreat to get their leader away from harm. Due to the heroism displayed by Captain Marvelous, Kaoru offers to have her Kuroko treat his wounds aboard the Gokai Galleon. Feeling the guilt over getting Captain Marvelous injured, Joe climbs up the crow's nest of the ship, thinking about his former comrade and what he has become. As the other Gokaigers gather to sleep around Captain Marvelous, Kaoru's retainer Toshizo Tanba tells her that the Ranger Keys are stored in the treasure chest with Navi sitting on it and tells her now is a good opportunity to take the Shinkenger Keys. She hits him with her fan in response and tells him she wants to continue observing the Gokaigers. The next morning, Luka notifies everyone that Joe is missing and he has left them a note, telling everyone that there is a matter he needs to settle alone.